/* ══════════════════════════════════════════════════════════════════════════════
   src/features/lesson/lesson.css
   Lesson viewer (/lesson/:id) — sections, ToC, embedded blocks, reader prefs.
   Design tokens come from themes.css; markdown body styling comes from
   markdown.css (this file never restyles .md-content itself).
   ══════════════════════════════════════════════════════════════════════════════ */

.lesson-view {
  margin: 0 auto;
}

.lesson-view--loading,
.lesson-view--error {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--color-text-secondary);
}

.lesson-view__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.lesson-view__title {
  font-size: clamp(1.5rem, 4vw, 2.1rem);
  line-height: 1.3;
  margin: 0;
  color: var(--color-text-primary);
}

.lesson-view__info-btn {
  padding: 0.4rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  cursor: pointer;
}

.lesson-comments {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}

.lesson-comments__hint {
  color: var(--color-text-secondary);
}

.lesson-comment {
  margin: .75rem 0;
  padding: .75rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
}

.lesson-comment time {
  margin-inline-start: .6rem;
  color: var(--color-text-secondary);
  font-size: .85rem;
}

.lesson-comment p {
  margin: .5rem 0 0;
  white-space: pre-wrap;
}

.lesson-comments__form {
  display: grid;
  gap: .6rem;
  margin-top: 1rem;
}

.lesson-comments__form textarea {
  display: block;
  box-sizing: border-box;
  width: 100%;
  min-height: 5rem;
  margin-top: .35rem;
  padding: .6rem;
  color: inherit;
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font: inherit;
}

.lesson-comments__form button {
  justify-self: start;
  padding: .55rem 1rem;
  border: 0;
  border-radius: 8px;
  background: var(--color-primary);
  color: #fff;
  font: inherit;
  cursor: pointer;
}

/* ── Sections ──────────────────────────────────────────────────────────────── */

.lesson-section {
  margin-bottom: 2.5rem;
  scroll-margin-top: 5rem;
  /* so ToC jumps clear any sticky header */
}

.lesson-section__header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 0.75rem;
}

.lesson-section__title {
  font-size: 1.3rem;
  margin: 0;
  color: var(--color-text-primary);
}

.lesson-block {
  margin-bottom: 1.1rem;
}

.lesson-block--media img,
.lesson-block--media video {
  max-width: 100%;
  border-radius: 10px;
}

/* ── Embedded question ─────────────────────────────────────────────────────── */

.lesson-question {
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 1rem;
}

.lesson-question__options {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

.lesson-question__option {
  text-align: start;
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: inherit;
  font: inherit;
  cursor: pointer;
}

.lesson-question__option:hover:not(:disabled) {
  border-color: var(--color-primary);
}

.lesson-question__option:disabled {
  cursor: default;
}

.lesson-question__option.is-correct {
  border-color: #22c55e;
  background: rgba(34, 197, 94, 0.12);
}

.lesson-question__option.is-wrong {
  border-color: #ef4444;
  background: rgba(239, 68, 68, 0.12);
}

.lesson-question__option.is-selected {
  border-color: var(--color-primary);
  background: var(--color-primary-light, rgba(99, 102, 241, 0.1));
}

.lesson-question__check-btn {
  margin-top: 0.75rem;
  padding: 0.5rem 1rem;
  border: 0;
  border-radius: 8px;
  background: var(--color-primary);
  color: #fff;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

.lesson-question__feedback {
  margin-top: 0.8rem;
}

.lesson-question__verdict {
  font-weight: 700;
}

.lesson-question__verdict.is-correct {
  color: #22c55e;
}

.lesson-question__verdict.is-wrong {
  color: #ef4444;
}

/* ── Embedded question: essay variant ────────────────────────────────────────
   Free-text self-check instead of the MCQ's option buttons — see
   lesson-blocks.js's renderEssayQuestionBody()/revealEssayAnswer(). */

.lesson-question__essay-input {
  width: 100%;
  margin-top: 0.75rem;
  padding: 0.6rem 0.8rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: inherit;
  font: inherit;
  resize: vertical;
  box-sizing: border-box;
}

.lesson-question__essay-input:disabled {
  opacity: 0.75;
  cursor: default;
}

.lesson-question__essay-input:placeholder-shown {
  color: var(--color-text-secondary);
  direction: rtl;
}

.lesson-question__essay-actions {
  margin-top: 0.6rem;
}

.lesson-question__essay-check-btn {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 8px;
  background: var(--color-primary);
  color: #fff;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

.lesson-question__essay-check-btn:disabled {
  opacity: 0.6;
  cursor: default;
}

.lesson-question__model-answer {
  margin-top: 0.5rem;
  padding: 0.6rem 0.8rem;
  border-radius: 8px;
  background: var(--color-primary-light, rgba(99, 102, 241, 0.1));
}

/* ── Quiz reference ────────────────────────────────────────────────────────── */

.lesson-block--quiz-ref {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 0.9rem 1rem;
}

.lesson-quiz-ref__label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-secondary);
}

.lesson-quiz-ref__title {
  margin: 0.2rem 0;
  font-size: 1.05rem;
}

.lesson-quiz-ref__count {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.lesson-quiz-ref__link {
  padding: 0.5rem 1rem;
  border-radius: 8px;
  background: var(--color-primary);
  color: #fff;
  text-decoration: none;
  white-space: nowrap;
}

/* ── Reader prefs + TTS ────────────────────────────────────────────────────── */

.lesson-prefs {
  position: relative;
}

.lesson-prefs__toggle,
.lesson-tts__btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.4rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
}

.lesson-prefs__toggle:hover,
.lesson-tts__btn:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

/* .lesson-tts__btn.is-speaking / .is-paused styling: see the Phase 3 TTS
   toolbar rules further down (kept there alongside the toolbar/stop button
   they were introduced with). */

.lesson-prefs__panel {
  position: absolute;
  inset-inline-end: 0;
  top: calc(100% + 0.4rem);
  z-index: 20;
  min-width: 230px;
  padding: 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-bg, #fff);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.14);
}

.lesson-prefs__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem;
  margin-bottom: 0.7rem;
  font-size: 0.9rem;
}

.lesson-prefs__row:last-child {
  margin-bottom: 0;
}

@media (max-width: 760px) {

  /* Sidebar column collapses into normal document flow — the shared
     .doc-toc mobile drawer owns the actual ToC presentation. */
  .lesson-view__layout {
    grid-template-columns: minmax(0, 1fr);
  }

  .lesson-view__sidebar {
    position: static;
    max-height: none;
    overflow-y: visible;
    order: -1;
  }
}

/* Modern lesson dashboard surfaces */
.lesson-view {
  max-width: 1180px;
  padding: clamp(1rem, 3vw, 2.5rem) clamp(.75rem, 2vw, 1.5rem) 5rem;
}

.lesson-view__header {
  align-items: center;
  padding: clamp(1rem, 2.5vw, 1.75rem);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  background: var(--color-surface, transparent);
  box-shadow: 0 8px 28px rgb(0 0 0 / .045);
}

.lesson-view__heading {
  flex: 0 0 auto;
  min-width: 0;
}

.lesson-view__eyebrow {
  margin: 0 0 .4rem;
  color: var(--color-primary);
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .04em;
}

.lesson-view__subtitle {
  margin: .5rem 0 0;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ── Phase 1: dashboard layout — main content + sticky ToC sidebar ───────────
   Two columns on desktop (content, then a narrower sidebar column — RTL
   flow means the sidebar renders on the visual left without any explicit
   left/right rule, since this is a plain two-track grid). Below 760px this
   collapses to one column and the sidebar's only child (.lesson-toc)
   reverts to lesson-toc.js's existing floating-toggle/drawer behavior — see
   that media query further down. */
.lesson-view__layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 260px);
  align-items: start;
  gap: clamp(1rem, 2.5vw, 1.75rem);
}

.lesson-view__layout--no-sidebar {
  grid-template-columns: minmax(0, 1fr);
}

.lesson-view__main {
  min-width: 0;
}

.lesson-view__sidebar {
  position: sticky;
  /* Clears the same amount of space .lesson-section's scroll-margin-top
     already reserves for a sticky header, so the sidebar and a
     scrolled-to section land at consistent heights. */
  top: 5rem;
  max-height: calc(100vh - 6rem);
  overflow-y: auto;
}

.lesson-view__body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1rem;
}

.lesson-section {
  padding: clamp(1rem, 2.5vw, 1.75rem);
  margin: 0 0 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: 18px;
  background: var(--color-surface, transparent);
  box-shadow: 0 5px 20px rgb(0 0 0 / .035);
}

.lesson-section__header {
  flex-wrap: wrap;
}

.lesson-view__info-btn,
.lesson-prefs__toggle {
  min-height: 42px;
  transition: background .18s ease, border-color .18s ease;
}

.lesson-view__info-btn:hover,
.lesson-prefs__toggle:hover {
  background: var(--color-surface-hover, var(--color-surface));
}

.lesson-prefs__panel {
  padding: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 14px;
  background: var(--color-surface, Canvas);
  box-shadow: 0 12px 32px rgb(0 0 0 / .12);
}

.lesson-comments {
  scroll-margin-top: 5rem;
  padding: clamp(1rem, 3vw, 1.75rem);
  border: 1px solid var(--color-border);
  border-radius: 18px;
  background: var(--color-surface, transparent);
}

.lesson-comment {
  padding: 1rem;
  border-radius: 14px;
  background: var(--color-surface, transparent);
}

/* ── Phase 4: تعليقات الدرس ─────────────────────────────────────────────────── */

.lesson-comments__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
}

.lesson-comments__sort {
  display: flex;
  gap: .35rem;
  flex-wrap: wrap;
}

.lesson-comments__sort-btn {
  padding: .35rem .8rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: .85rem;
  cursor: pointer;
  transition: background var(--lesson-transition, .15s ease), color var(--lesson-transition, .15s ease), border-color var(--lesson-transition, .15s ease);
}

.lesson-comments__sort-btn:hover {
  border-color: var(--color-primary);
}

.lesson-comments__sort-btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.lesson-comments__sort-btn.is-active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.lesson-comments__list {
  display: grid;
  gap: .75rem;
  margin: 1rem 0;
}

.lesson-comments__skeleton {
  height: 4.5rem;
  border-radius: 12px;
  background: linear-gradient(90deg, var(--color-border) 25%, color-mix(in srgb, var(--color-border) 60%, transparent) 37%, var(--color-border) 63%);
  background-size: 400% 100%;
  animation: lesson-comment-shimmer 1.4s ease infinite;
}

@keyframes lesson-comment-shimmer {
  0% {
    background-position: 100% 50%;
  }

  100% {
    background-position: 0 50%;
  }
}

.lesson-comments__empty,
.lesson-comments__error,
.lesson-comments__pending-note {
  color: var(--color-text-secondary);
  padding: .5rem 0;
}

.lesson-comments__error {
  color: #c0392b;
}

.lesson-comments__more {
  display: block;
  margin: .5rem auto 0;
  padding: .5rem 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: transparent;
  color: var(--color-text-primary, inherit);
  font: inherit;
  cursor: pointer;
}

.lesson-comment {
  scroll-margin-top: 5rem;
  transition: box-shadow var(--lesson-transition, .2s ease);
}

.lesson-comment--highlighted {
  box-shadow: 0 0 0 2px var(--color-primary);
}

.lesson-comment__meta {
  display: flex;
  align-items: baseline;
  gap: .5rem;
  flex-wrap: wrap;
}

.lesson-comment__meta time {
  color: var(--color-text-secondary);
  font-size: .8rem;
}

.lesson-comment__body {
  margin: .5rem 0 0;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.lesson-comment__actions {
  display: flex;
  flex-wrap: wrap;
  gap: .9rem;
  margin-top: .6rem;
}

.lesson-comment__react {
  display: inline-flex;
  align-items: center;
  gap: .3rem;
  padding: .25rem .6rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: .82rem;
  cursor: pointer;
}

.lesson-comment__react.is-active {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.lesson-comment__react:focus-visible,
.lesson-comment__link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.lesson-comment__link {
  background: none;
  border: 0;
  padding: 0;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: .82rem;
  text-decoration: underline;
  cursor: pointer;
}

.lesson-comment__link--danger {
  color: #c0392b;
}

.lesson-comment__replies {
  display: grid;
  gap: .6rem;
  margin-top: .75rem;
  padding-inline-start: 1.25rem;
  border-inline-start: 2px solid var(--color-border);
}

.lesson-comment--reply {
  padding: .75rem;
}

.lesson-comment__reply-slot:empty {
  margin: 0;
}

.lesson-comments__form,
.lesson-comment__edit-form {
  display: grid;
  gap: .5rem;
  margin-top: .75rem;
}

.lesson-comments__form--reply {
  padding-inline-start: 1.25rem;
  border-inline-start: 2px solid var(--color-border);
}

.lesson-comments__form textarea,
.lesson-comment__edit-form textarea {
  display: block;
  box-sizing: border-box;
  width: 100%;
  min-height: 4.5rem;
  padding: .6rem;
  color: inherit;
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font: inherit;
}

.lesson-comments__form textarea:focus-visible,
.lesson-comment__edit-form textarea:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.lesson-comments__form-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .6rem;
}

.lesson-comments__count {
  color: var(--color-text-secondary);
  font-size: .8rem;
}

.lesson-comments__form-row button,
.lesson-comment__edit-form button {
  padding: .5rem 1rem;
  border: 0;
  border-radius: 8px;
  background: var(--color-primary);
  color: #fff;
  font: inherit;
  cursor: pointer;
}

.lesson-comments__form-row button[data-action="cancel-reply"],
.lesson-comment__edit-form button[data-action="cancel-edit"] {
  background: transparent;
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
}

.lesson-comment__reply-badge {
  padding: .1rem .5rem;
  border-radius: 999px;
  background: var(--color-border);
  color: var(--color-text-secondary);
  font-size: .72rem;
}

.lesson-comment__parent-snippet {
  margin: .25rem 0 0;
  color: var(--color-text-secondary);
  font-size: .85rem;
  font-style: italic;
}

@media (max-width: 640px) {
  .lesson-view__header {
    border-radius: 14px;
  }

  .lesson-section {
    border-radius: 14px;
  }
}

@media (prefers-reduced-motion: reduce) {

  .lesson-view *,
  .lesson-view *::before,
  .lesson-view *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}

/* Lesson bookmarks */
.lesson-bookmarks {
  position: relative;
}

.lesson-bookmarks__toggle,
.lesson-bookmark-btn {
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-primary);
  border-radius: .65rem;
  padding: .55rem .75rem;
  cursor: pointer;
}

.lesson-bookmark-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  width: 2rem;
  height: 2rem;
  min-width: 2rem;
  min-height: 2rem;
  padding: .35rem;
  line-height: 1;
}

/* The section bookmark button is intentionally smaller than the header
   actions. Give its inline SVG an explicit viewport so it cannot collapse or
   inherit an unexpected intrinsic size from another global rule. */
.lesson-bookmark-btn .lesson-icon {
  display: block;
  width: 1rem;
  height: 1rem;
  flex: 0 0 1rem;
}

.lesson-bookmark-btn.is-active {
  background: var(--color-primary-light, rgba(99, 102, 241, 0.14));
  border-color: var(--color-primary);
}

.lesson-bookmarks__panel {
  position: absolute;
  z-index: 20;
  inset-inline-end: 0;
  top: calc(100% + .4rem);
  width: min(22rem, calc(100vw - 2rem));
  max-height: 50vh;
  overflow: auto;
  padding: .75rem;
  border: 1px solid var(--color-border);
  border-radius: .85rem;
  background: var(--color-surface);
  color: var(--color-text-primary);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.14);
}

.lesson-bookmarks__item {
  display: flex;
  align-items: center;
  gap: .5rem;
  justify-content: space-between;
  padding: .45rem 0;
  border-bottom: 1px solid var(--color-border);
}

.lesson-bookmarks__item button {
  color: inherit;
  background: transparent;
  border: 0;
  cursor: pointer;
  text-align: start;
}

.lesson-bookmarks__item button:first-child {
  flex: 1;
}

.lesson-section {
  scroll-margin-top: 6rem;
}

.lesson-section:focus {
  outline: 2px solid var(--accent-color, #3b82f6);
  outline-offset: 4px;
}

@media (prefers-reduced-motion: reduce) {
  .lesson-view * {
    scroll-behavior: auto !important;
    transition-duration: .01ms !important;
  }
}

/* ── Phase 3: reading width / text size ───────────────────────────────────
   Set as CSS vars by applyReaderPrefs() in lesson-reader-prefs.js; default
   to Phase 1/2's fixed values so a lesson rendered before these vars exist
   (e.g. mid-deploy) still looks correct.
   Scoped to .lesson-view__main (the content column), NOT the whole
   .lesson-view article: the reader's reading-width choice is a preference
   about paragraph measure, not about how wide the header or the ToC
   sidebar sit — constraining the whole dashboard here would fight Phase
   1's layout every time the reader picked anything narrower than 1180px.
   font-size still applies via .lesson-view so TTS/quiz/comments text below
   the content column also honors the reader's text-size choice. */
.lesson-view {
  --lesson-reading-width: 820px;
  --lesson-reading-text-size: 1rem;
  font-size: var(--lesson-reading-text-size);
}

.lesson-view__main {
  max-width: var(--lesson-reading-width);
}


.lesson-prefs__row--switch {
  justify-content: space-between;
}

.lesson-prefs__row select {
  color: var(--color-text-primary);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: .3rem .5rem;
  font: inherit;
}

/* Chromium (the OS-native <select> popup listbox, not the closed box) can
   ignore an ancestor's color-scheme for its own background/text unless the
   select/option elements themselves carry an explicit color declaration —
   "color: inherit; background: transparent" above styles the closed box
   correctly but leaves the opened popup rendered with the OS's light
   default regardless of the active theme. Setting it directly here (also
   covers .lesson-tts__speed-select, which had the same transparent-only
   rule further below) fixes that without touching color-scheme itself. */
.lesson-prefs__row select option,
.lesson-tts__speed-select option {
  color: var(--color-text-primary);
  background: var(--color-surface);
}

/* ── Phase 3: TTS toolbar ─────────────────────────────────────────────────
   Replaces the old single play/pause button with a small persistent
   toolbar: toggle (play/pause/resume), stop, and a speed selector. */
.lesson-tts {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.lesson-tts__btn--stop {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: var(--color-text-secondary);
  font-size: 0.8rem;
  cursor: pointer;
}

.lesson-tts__btn--stop:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.lesson-tts__btn.is-speaking,
.lesson-tts__btn.is-paused {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.lesson-tts__speed {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.82rem;
  color: var(--color-text-secondary);
}

.lesson-tts__speed-select {
  color: var(--color-text-primary);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 0.25rem 0.4rem;
  font: inherit;
  font-size: 0.82rem;
  cursor: pointer;
}

/* ── Phase 3: active-paragraph state is fully owned by TTS controls. */

/* ── Phase 5: text-selection AI popup ("اشرح ده / بسّطها") ────────────────
   Fixed-position, JS-placed above (or, if clipped, below) the selection —
   see lesson-selection-actions.js. Uses the same floating-control surface
   treatment as .lesson-prefs__panel (solid surface + shadow, not glass, per
   the plan's "glass only on floating controls" rule — this IS a floating
   control). RTL-agnostic: it has no inline-direction-sensitive offsets of
   its own, only top/left set from getBoundingClientRect(), which is
   already writing-direction-independent. */
.lesson-selection-popup {
  position: fixed;
  z-index: 40;
  display: flex;
  gap: 0.35rem;
  padding: 0.35rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-surface, var(--color-bg, #fff));
  box-shadow: var(--shadow-md, 0 8px 24px rgba(0, 0, 0, 0.14));
}

.lesson-selection-popup__btn {
  padding: 0.4rem 0.75rem;
  border: 1px solid transparent;
  border-radius: 7px;
  background: var(--color-primary);
  color: #fff;
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color 0.15s ease;
}

.lesson-selection-popup__btn:hover {
  background: var(--color-primary-hover, var(--color-primary));
}

.lesson-selection-popup__btn:focus-visible {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .lesson-selection-popup__btn {
    transition: none;
  }
}

/* ── Phase 5: per-lesson progress summary (in the lesson info modal) ────── */

.lesson-progress-summary {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.lesson-progress-summary__bar-track {
  height: 8px;
  border-radius: 999px;
  background: var(--color-background-secondary, var(--color-border));
  overflow: hidden;
}

.lesson-progress-summary__bar-fill {
  height: 100%;
  border-radius: 999px;
  background: var(--color-primary);
  transition: width 0.3s ease;
}

@media (prefers-reduced-motion: reduce) {
  .lesson-progress-summary__bar-fill {
    transition: none;
  }
}

.lesson-progress-summary__headline {
  margin: 0;
  font-weight: 700;
  color: var(--color-text-primary);
}

.lesson-progress-summary__done {
  font-weight: 600;
  color: var(--color-success, #22c55e);
}

.lesson-progress-summary__stats {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.lesson-progress-summary__resume {
  align-self: flex-start;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: var(--color-primary);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}

.lesson-progress-summary__resume:hover {
  border-color: var(--color-primary);
  background: var(--color-primary-light, rgba(99, 102, 241, 0.08));
}

.lesson-progress-summary__resume:focus-visible {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

/* ── Phase 5: AI study actions (in the lesson info modal) ────────────────
   Shell (.quiz-info-section etc.) comes from the shared quiz-info-modal.css,
   already loaded globally — only the button wrap/buttons themselves are
   new. Pill style, matching .quiz-metric-pill's rounded/compact language
   rather than the block-level .lesson-question__check-btn treatment, since
   several of these sit side by side. */

.lesson-info-modal__ai-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.lesson-info-modal__ai-action {
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease, background-color 0.15s ease;
}

.lesson-info-modal__ai-action:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background: var(--color-primary-light, rgba(99, 102, 241, 0.06));
}

.lesson-info-modal__ai-action:focus-visible {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .lesson-info-modal__ai-action {
    transition: none;
  }
}

/* ── Phase 5: "explain my wrong answer" trigger (embedded question feedback) */

.lesson-question__explain-wrong-btn {
  margin-top: 0.6rem;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: var(--color-primary);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease;
}

.lesson-question__explain-wrong-btn:hover {
  border-color: var(--color-primary);
  background: var(--color-primary-light, rgba(99, 102, 241, 0.08));
}

.lesson-question__explain-wrong-btn:focus-visible {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .lesson-question__explain-wrong-btn {
    transition: none;
  }
}

/* ── Phase 6: remaining unstyled-leaf cleanup ─────────────────────────────
   Everything below was a real gap found in the final regression sweep:
   referenced in JS, matched no selector anywhere in the lesson page's
   loaded stylesheet chain. Question sub-parts already carry md-content
   (typography) so these only add the layout/spacing md-content itself
   doesn't own. */

.lesson-question__prompt {
  margin-bottom: 0.6rem;
  font-weight: 600;
}

.lesson-question__option-text {
  display: inline;
}

.lesson-question__explanation {
  margin-top: 0.6rem;
  padding-top: 0.6rem;
  border-top: 1px dashed var(--color-border);
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

/* Retry button: same secondary-action language as .lesson-question__explain-wrong-btn,
   shown only after a graded attempt (toggled via the `hidden` attribute in JS). */
.lesson-section__body {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.lesson-tts__btn--play {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.lesson-quiz-ref__info {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  min-width: 0;
}

.lesson-ai-quiz__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.lesson-info-modal__bookmarks-section {
  margin-top: 0.75rem;
}


/* ═══════════════════════════════════════════════════════════════════════════
   Lesson final interaction/layout pass
   These selectors intentionally live at the end of this feature stylesheet
   so the lesson-specific surfaces win over the earlier phase rules without
   changing shared document/quiz styles elsewhere.
   ═══════════════════════════════════════════════════════════════════════════ */

.lesson-view__header {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.lesson-view__heading {
  min-width: 0;
}

.lesson-view__header-actions {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  flex-wrap: wrap;
  gap: .55rem;
  min-width: 0;
}

.lesson-view__header-actions>* {
  flex: 0 0 auto;
}

.lesson-reset-all {
  min-height: 42px;
  padding: .4rem .8rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: .85rem;
  cursor: pointer;
}

.lesson-reset-all:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background: var(--color-surface-hover, var(--color-surface));
}

.lesson-reset-all:disabled {
  opacity: .55;
  cursor: wait;
}

.lesson-view__layout {
  display: block;
  width: 100%;
  max-width: 100%;
}

.lesson-view__main {
  width: min(100%, var(--lesson-reading-width, 820px));
  max-width: var(--lesson-reading-width, 820px);
  margin-inline: auto;
  min-width: 0;
}

.lesson-view__body {
  width: 100%;
  max-width: 100%;
  margin-inline: auto;
}

.lesson-section {
  width: 100%;
  max-width: 100%;
  margin-inline: auto;
  box-sizing: border-box;
  overflow-wrap: anywhere;
}

.lesson-section__header {
  min-width: 0;
}

.lesson-section__title {
  min-width: 0;
  overflow-wrap: anywhere;
}

.lesson-block--markdown,
.lesson-question,
.lesson-block--quiz-ref,
.lesson-block--media {
  min-width: 0;
}

.lesson-block--media img,
.lesson-block--media video,
.lesson-block--media audio,
.lesson-block--media iframe {
  max-width: 100%;
}

/* Shared reader panel: no reader-level highlight row remains. */
.lesson-prefs__panel {
  min-width: min(240px, calc(100vw - 2rem));
  max-width: min(320px, calc(100vw - 2rem));
  box-sizing: border-box;
}

.lesson-prefs__row {
  min-width: 0;
}

.lesson-prefs__row select {
  min-width: 0;
  max-width: 11rem;
}

/* The old question reset is intentionally gone; this is the only global
   reset action rendered by the lesson viewer. */

/* ── Dedicated settings section in the information dialog ──────────────── */
.lesson-info-modal__prefs {
  margin: 0;
  padding: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 14px;
  background: var(--color-surface, transparent);
  box-shadow: inset 0 1px 0 rgb(255 255 255 / .025);
}

.lesson-info-modal__prefs-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: .8rem;
  margin-bottom: .9rem;
}

.lesson-info-modal__prefs-head h3 {
  margin: 0;
  color: var(--color-text-primary);
  font-size: 1rem;
}

.lesson-info-modal__prefs-head p {
  margin: .3rem 0 0;
  color: var(--color-text-secondary);
  font-size: .8rem;
  line-height: 1.6;
}

/* Essay mirrors must stay inside the native textarea viewport; otherwise
   highlighted overflow can escape the field and overlap feedback/actions. */
.lesson-question__essay-wrap > .rich-input-highlighter--field {
  min-width: 0;
  overflow: hidden;
  border-radius: 10px;
}
.lesson-question__essay-wrap .rich-input-highlighter__mirror {
  overflow: hidden;
}

.lesson-info-modal__prefs-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .7rem;
}

.lesson-info-modal__prefs-grid>label {
  display: grid;
  gap: .35rem;
  min-width: 0;
  color: var(--color-text-secondary);
  font-size: .82rem;
}

.lesson-info-modal__prefs-grid select,
.lesson-info-modal__prefs-grid input:not([type="checkbox"]) {
  box-sizing: border-box;
  width: 100%;
  min-width: 0;
  padding: .55rem .65rem;
  border: 1px solid var(--color-border);
  border-radius: 9px;
  background: var(--color-surface, transparent);
  color: var(--color-text-primary);
  font: inherit;
}

.lesson-info-modal__prefs-grid select option {
  background: var(--color-surface);
  color: var(--color-text-primary);
}

.lesson-info-modal__prefs-switch {
  grid-template-columns: minmax(0, 1fr) auto !important;
  align-items: center;
  min-height: 2.35rem;
  padding: .45rem .65rem;
  border: 1px solid var(--color-border);
  border-radius: 9px;
}

.lesson-info-modal__prefs-switch input[type="checkbox"] {
  width: 1.1rem;
  height: 1.1rem;
  margin: 0;
  accent-color: var(--color-primary);
}

/* ── Robust read-aloud toolbar ─────────────────────────────────────────── */
.lesson-tts {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  flex-wrap: wrap;
  max-width: 100%;
  min-width: 0;
}

.lesson-tts__btn {
  min-height: 36px;
}

.lesson-tts__btn--stop[hidden] {
  display: none !important;
}

.lesson-tts__speed {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  min-height: 36px;
  color: var(--color-text-secondary);
  font-size: .8rem;
}

.lesson-tts__speed-select {
  min-width: 4.1rem;
  padding: .35rem .45rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface);
  color: var(--color-text-primary);
  font: inherit;
}

.lesson-tts__status {
  min-width: 0;
  max-width: 20rem;
  color: var(--color-text-secondary);
  font-size: .76rem;
  line-height: 1.45;
}

.lesson-tts__status.is-loading {
  color: var(--color-primary);
}

.lesson-tts__status.is-error {
  color: var(--color-danger, #dc2626);
}

.lesson-tts--unsupported .lesson-tts__status {
  color: var(--color-text-secondary);
}

.lesson-tts-block--active {
  border-radius: 6px;
  background: var(--color-primary-light, rgb(99 102 241 / .13));
  box-shadow: 0 0 0 3px var(--color-primary-light, rgb(99 102 241 / .08));
  transition: background-color .18s ease, box-shadow .18s ease;
}

/* ── Interactive embedded questions ───────────────────────────────────── */
.lesson-question {
  padding: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 14px;
  background: var(--color-surface, transparent);
}

.lesson-question__options {
  display: grid;
  gap: .55rem;
  margin-top: .8rem;
}

.lesson-question__option {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: .7rem;
  width: 100%;
  box-sizing: border-box;
  min-height: 3rem;
  padding: .65rem .75rem;
  text-align: start;
  overflow: hidden;
}

.lesson-question__option-text {
  min-width: 0;
  overflow-wrap: anywhere;
  line-height: 1.65;
}

.lesson-question__option.is-selected {
  border-color: var(--color-primary);
  background: var(--color-primary-light, rgb(99 102 241 / .1));
}

.lesson-question__option.is-correct {
  border-color: var(--color-success, #22c55e);
  background: color-mix(in srgb, var(--color-success, #22c55e) 12%, transparent);
}

.lesson-question__option.is-wrong {
  border-color: var(--color-danger, #ef4444);
  background: color-mix(in srgb, var(--color-danger, #ef4444) 12%, transparent);
}

.lesson-question__check-btn,
.lesson-question__essay-check-btn {
  margin-top: .75rem;
}

/* ── Advanced ephemeral AI quiz ────────────────────────────────────────── */
.lesson-ai-quiz {
  width: 100%;
  box-sizing: border-box;
  margin: 2rem 0 0;
  padding: clamp(1rem, 2.5vw, 1.35rem);
  border: 1px solid color-mix(in srgb, var(--color-primary) 70%, var(--color-border));
  border-radius: 18px;
  background: var(--color-surface, transparent);
  box-shadow: 0 10px 30px rgb(0 0 0 / .045);
  overflow: hidden;
}

.lesson-ai-quiz__header {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: start;
  gap: .8rem;
  margin: 0;
}

.lesson-ai-quiz__heading {
  min-width: 0;
}

.lesson-ai-quiz__badge {
  display: inline-flex;
  align-items: center;
  min-height: 1.55rem;
  padding: .15rem .55rem;
  border-radius: 999px;
  background: var(--color-primary-light, rgb(99 102 241 / .12));
  color: var(--color-primary);
  font-size: .74rem;
  font-weight: 700;
}

.lesson-ai-quiz__header h2 {
  margin: .4rem 0 0;
  color: var(--color-text-primary);
  font-size: clamp(1.05rem, 2.4vw, 1.35rem);
  line-height: 1.5;
  overflow-wrap: anywhere;
}

.lesson-ai-quiz__header p {
  margin: .25rem 0 0;
  color: var(--color-text-secondary);
  font-size: .8rem;
}

.lesson-ai-quiz__close {
  display: inline-flex;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  padding: 0;
  border: 1px solid var(--color-border) !important;
  border-radius: 999px !important;
  background: transparent !important;
  color: var(--color-text-secondary) !important;
  font-size: 1.25rem;
  line-height: 1;
}

.lesson-ai-quiz__close:hover {
  color: var(--color-text-primary) !important;
  border-color: var(--color-primary) !important;
}

.lesson-ai-quiz__meta {
  display: grid;
  gap: .55rem;
  margin-top: 1rem;
  padding: .8rem .9rem;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: color-mix(in srgb, var(--color-surface-hover, transparent) 70%, transparent);
}

.lesson-ai-quiz__progress-line {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: .7rem;
  flex-wrap: wrap;
  color: var(--color-text-secondary);
  font-size: .8rem;
}

.lesson-ai-quiz__progress-track {
  height: 7px;
  border-radius: 999px;
  overflow: hidden;
  background: var(--color-border);
}

.lesson-ai-quiz__progress-track>span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: var(--color-primary);
  transition: width .2s ease;
}

.lesson-ai-quiz__nav {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem;
  direction: rtl;
}

.lesson-ai-quiz__nav-dot {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0;
  border: 1px solid var(--color-border);
  border-radius: .65rem;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: .78rem;
  cursor: pointer;
}

.lesson-ai-quiz__nav-dot:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.lesson-ai-quiz__nav-dot.is-answered {
  border-color: color-mix(in srgb, var(--color-primary) 45%, var(--color-border));
  color: var(--color-text-primary);
}

.lesson-ai-quiz__nav-dot.is-active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.lesson-ai-quiz__question {
  min-width: 0;
  margin-top: 1rem;
  padding: clamp(.95rem, 2vw, 1.2rem);
  border: 1px solid var(--color-border);
  border-radius: 14px;
  overflow: hidden;
}

.lesson-ai-quiz__question-kicker {
  margin-bottom: .45rem;
  color: var(--color-primary);
  font-size: .78rem;
  font-weight: 700;
}

.lesson-ai-quiz__question h3 {
  margin: 0;
  color: var(--color-text-primary);
  font-size: clamp(1rem, 2.25vw, 1.25rem);
  line-height: 1.75;
  overflow-wrap: anywhere;
}

.lesson-ai-quiz__options {
  display: grid;
  gap: .55rem;
  margin-top: 1rem;
}

.lesson-ai-quiz__option {
  display: grid;
  grid-template-columns: 2rem auto minmax(0, 1fr);
  align-items: center;
  gap: .65rem;
  width: 100%;
  min-width: 0;
  box-sizing: border-box;
  padding: .7rem .75rem;
  border: 1px solid var(--color-border);
  border-radius: 11px;
  background: transparent;
  color: var(--color-text-primary);
  cursor: pointer;
  text-align: start;
  transition: border-color .15s ease, background-color .15s ease, box-shadow .15s ease;
}

.lesson-ai-quiz__option:hover {
  border-color: var(--color-primary);
  background: var(--color-surface-hover, rgb(127 127 127 / .06));
}

.lesson-ai-quiz__option input {
  margin: 0;
  accent-color: var(--color-primary);
}

.lesson-ai-quiz__option-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.9rem;
  height: 1.9rem;
  border: 1px solid var(--color-border);
  border-radius: .55rem;
  color: var(--color-text-secondary);
  font-size: .75rem;
  font-weight: 700;
}

.lesson-ai-quiz__option-text {
  min-width: 0;
  line-height: 1.65;
  overflow-wrap: anywhere;
}

.lesson-ai-quiz__option.is-selected {
  border-color: var(--color-primary);
  background: var(--color-primary-light, rgb(99 102 241 / .1));
  box-shadow: 0 0 0 2px var(--color-primary-light, rgb(99 102 241 / .08));
}

.lesson-ai-quiz__option.is-correct-option {
  border-color: var(--color-success, #22c55e);
  background: color-mix(in srgb, var(--color-success, #22c55e) 12%, transparent);
}

.lesson-ai-quiz__option.is-wrong-option {
  border-color: var(--color-danger, #ef4444);
  background: color-mix(in srgb, var(--color-danger, #ef4444) 12%, transparent);
}

.lesson-ai-quiz__text-wrap {
  display: grid;
  gap: .45rem;
  margin-top: 1rem;
}

.lesson-ai-quiz__text-label {
  color: var(--color-text-secondary);
  font-size: .8rem;
  font-weight: 600;
}

.lesson-ai-quiz__text {
  width: 100%;
  min-width: 0;
  box-sizing: border-box;
  padding: .8rem .85rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  color: var(--color-text-primary);
  background: var(--color-surface);
  font: inherit;
  line-height: 1.6;
}

.lesson-ai-quiz__text:focus-visible,
.lesson-ai-quiz__option:focus-within {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

.lesson-ai-quiz__feedback {
  margin-top: .9rem;
  padding: .75rem .85rem;
  border: 1px solid var(--color-border);
  border-radius: 11px;
  background: var(--color-surface-hover, rgb(127 127 127 / .07));
}

.lesson-ai-quiz__feedback-title {
  font-weight: 750;
}

.lesson-ai-quiz__feedback p {
  margin: .35rem 0 0;
  color: var(--color-text-secondary);
  line-height: 1.65;
  overflow-wrap: anywhere;
}

.lesson-ai-quiz__feedback.is-correct {
  border-color: color-mix(in srgb, var(--color-success, #22c55e) 45%, var(--color-border));
  color: var(--color-success, #16803d);
}

.lesson-ai-quiz__feedback.is-incorrect {
  border-color: color-mix(in srgb, var(--color-danger, #ef4444) 45%, var(--color-border));
  color: var(--color-danger, #c0392b);
}

.lesson-ai-quiz__feedback-note {
  font-size: .78rem;
}

.lesson-ai-quiz__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.lesson-ai-quiz__steps {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
}

.lesson-ai-quiz__step,
.lesson-ai-quiz__submit {
  min-height: 42px;
  padding: .55rem .9rem;
  border: 1px solid var(--color-border);
  border-radius: 9px;
  background: transparent;
  color: var(--color-text-primary);
  font: inherit;
  font-weight: 650;
  cursor: pointer;
}

.lesson-ai-quiz__submit {
  border-color: transparent;
  background: var(--color-primary);
  color: #fff;
}

.lesson-ai-quiz__step:hover:not(:disabled) {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.lesson-ai-quiz__submit:hover:not(:disabled) {
  background: var(--color-primary-hover, var(--color-primary));
}

.lesson-ai-quiz__step:disabled,
.lesson-ai-quiz__submit:disabled {
  opacity: .5;
  cursor: not-allowed;
}

.lesson-ai-quiz__close:focus-visible,
.lesson-ai-quiz__nav-dot:focus-visible,
.lesson-ai-quiz__step:focus-visible,
.lesson-ai-quiz__submit:focus-visible {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

/* ── Selection-popup loading/error state ───────────────────────────────── */
.lesson-selection-popup {
  display: flex;
  align-items: center;
  gap: .4rem;
  flex-wrap: wrap;
  max-width: min(90vw, 32rem);
  box-sizing: border-box;
}

.lesson-selection-popup__btn:disabled {
  opacity: .6;
  cursor: wait;
}

.lesson-selection-popup__status {
  flex: 1 1 100%;
  min-width: 0;
  color: var(--color-text-secondary);
  font-size: .74rem;
  line-height: 1.45;
}

.lesson-selection-popup__status.is-error {
  color: var(--color-danger, #dc2626);
}

/* ── Loading skeleton ──────────────────────────────────────────────────── */
.lesson-view--loading {
  width: min(100%, 1180px);
  margin-inline: auto;
  padding: clamp(1rem, 3vw, 2.5rem) clamp(.75rem, 2vw, 1.5rem) 5rem;
  box-sizing: border-box;
  text-align: start;
}

.lesson-skeleton__header,
.lesson-skeleton__layout,
.lesson-skeleton__section,
.lesson-skeleton__question {
  min-width: 0;
}

.lesson-skeleton__header {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(220px, auto);
  align-items: center;
  gap: 1.25rem;
  padding: clamp(1rem, 2.5vw, 1.75rem);
  margin-bottom: 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: 20px;
  background: var(--color-surface, transparent);
}

.lesson-skeleton__header-copy,
.lesson-skeleton__header-actions,
.lesson-skeleton__section,
.lesson-skeleton__question,
.lesson-skeleton__options {
  display: grid;
  align-content: start;
  gap: .65rem;
}

.lesson-skeleton__header-actions {
  grid-auto-flow: column;
  grid-auto-columns: minmax(64px, 1fr);
}

.lesson-skeleton__layout {
  display: block;
  width: 100%;
}

.lesson-skeleton__content {
  width: min(100%, 820px);
  margin-inline: auto;
  display: grid;
  gap: 1rem;
}

.lesson-skeleton__section {
  padding: clamp(1rem, 2.5vw, 1.75rem);
  border: 1px solid var(--color-border);
  border-radius: 18px;
  background: var(--color-surface, transparent);
}

.lesson-skeleton__question {
  margin-top: .15rem;
  padding: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 12px;
}

.lesson-skeleton__toc {
  position: fixed;
  inset: 50% auto auto 28px;
  width: 200px;
  padding: 14px 10px;
  transform: translateY(-50%);
  display: grid;
  gap: .55rem;
  border: 1px solid var(--color-border);
  border-radius: 14px;
  background: var(--color-surface, transparent);
}

.lesson-skeleton__line {
  display: block;
  width: var(--skeleton-width, 70%);
  max-width: 100%;
  height: .85rem;
  border-radius: 8px;
  background: linear-gradient(90deg, var(--color-surface-hover, rgb(127 127 127 / .1)) 0%, var(--color-border) 50%, var(--color-surface-hover, rgb(127 127 127 / .1)) 100%);
  background-size: 220% 100%;
  animation: lesson-shimmer 1.45s ease-in-out infinite;
}

.lesson-skeleton__line--2 {
  height: 1.35rem;
}

.lesson-skeleton__line--3 {
  opacity: .88;
}

.lesson-skeleton__line--4 {
  opacity: .72;
}

.lesson-skeleton__media {
  min-height: 9rem;
  border-radius: 12px;
  background: linear-gradient(90deg, var(--color-surface-hover, rgb(127 127 127 / .1)) 0%, var(--color-border) 50%, var(--color-surface-hover, rgb(127 127 127 / .1)) 100%);
  background-size: 220% 100%;
  animation: lesson-shimmer 1.45s ease-in-out infinite;
}

@keyframes lesson-shimmer {
  0% {
    background-position: 100% 0;
  }

  100% {
    background-position: -120% 0;
  }
}

.lesson-load-error {
  width: min(100%, 720px);
  margin: clamp(2rem, 8vh, 5rem) auto;
  padding: 2rem 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: 18px;
  background: var(--color-surface, transparent);
  box-sizing: border-box;
}

.lesson-load-error__icon {
  display: grid;
  place-items: center;
  width: 2.8rem;
  height: 2.8rem;
  margin: 0 auto 1rem;
  border-radius: 999px;
  background: var(--color-primary-light, rgb(99 102 241 / .1));
  color: var(--color-primary);
  font-weight: 800;
}

.lesson-load-error h1 {
  margin: 0;
  color: var(--color-text-primary);
}

.lesson-load-error p {
  margin: .6rem auto 0;
  max-width: 32rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.lesson-load-error__actions {
  display: flex;
  justify-content: center;
  gap: .6rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.lesson-view__retry-btn,
.lesson-view__back-btn {
  min-height: 42px;
  padding: .55rem .9rem;
  border-radius: 9px;
  font: inherit;
  text-decoration: none;
}

.lesson-view__retry-btn {
  border: 0;
  background: var(--color-primary);
  color: #fff;
  cursor: pointer;
}

.lesson-view__back-btn {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--color-border);
  color: var(--color-text-primary);
}

@media (max-width: 760px) {
  .lesson-view__header {
    grid-template-columns: 1fr;
  }

  .lesson-view__heading,
  .lesson-view__header-actions {
    grid-column: 1;
  }

  .lesson-view__header-actions {
    width: 100%;
    justify-content: flex-start;
  }

  .lesson-view__header-actions>.lesson-prefs,
  .lesson-view__header-actions>.lesson-bookmarks {
    max-width: 100%;
  }

  .lesson-skeleton__header {
    grid-template-columns: 1fr;
  }

  .lesson-skeleton__header-actions {
    grid-auto-flow: row;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .lesson-skeleton__toc {
    display: none;
  }

  .lesson-ai-quiz__footer {
    align-items: stretch;
  }

  .lesson-ai-quiz__steps,
  .lesson-ai-quiz__submit {
    width: 100%;
  }

  .lesson-ai-quiz__steps>* {
    flex: 1 1 0;
  }

  .lesson-info-modal__prefs-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  .lesson-view--loading * {
    animation: none !important;
  }

  .lesson-tts-block--active,
  .lesson-ai-quiz__progress-track>span {
    transition: none !important;
  }
}

/* ── Final AI quiz layout pass ─────────────────────────────────────────── */
.lesson-ai-quiz {
  margin: 1.25rem 0 0;
  padding: clamp(.9rem, 2vw, 1.25rem);
}

.lesson-ai-quiz__header {
  position: relative;
  display: block;
  min-width: 0;
  padding-inline-end: 3rem;
}

.lesson-ai-quiz__heading {
  min-width: 0;
  text-align: start;
}

.lesson-ai-quiz__header p {
  max-width: 52rem;
}

.lesson-ai-quiz__close {
  position: absolute;
  inset-inline-end: 0;
  inset-block-start: 0;
  width: 2.35rem;
  height: 2.35rem;
  border-radius: 10px !important;
  font-size: 1.35rem;
}

.lesson-ai-quiz__meta {
  margin-top: .8rem;
  padding: .7rem .8rem;
  gap: .45rem;
}

.lesson-ai-quiz__progress-line {
  font-size: .78rem;
}

.lesson-ai-quiz__nav {
  justify-content: flex-start;
  gap: .3rem;
}

.lesson-ai-quiz__nav-dot {
  width: 1.9rem;
  height: 1.9rem;
}

.lesson-ai-quiz__question {
  margin-top: .8rem;
  padding: clamp(.85rem, 2vw, 1.1rem);
}

.lesson-ai-quiz__question h3 {
  max-width: 70ch;
}

.lesson-ai-quiz__options {
  gap: .5rem;
  margin-top: .85rem;
}

.lesson-ai-quiz__option {
  grid-template-columns: 2rem minmax(0, 1fr) auto;
  gap: .6rem;
  min-height: 2.9rem;
  padding: .62rem .7rem;
}

.lesson-ai-quiz__option-text {
  text-align: start;
}

.lesson-ai-quiz__option input {
  width: 1.05rem;
  height: 1.05rem;
  justify-self: end;
}

.lesson-ai-quiz__text-wrap {
  margin-top: .85rem;
}

.lesson-ai-quiz__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
  margin-top: .85rem;
  min-width: 0;
}

.lesson-ai-quiz__submit {
  order: 2;
  margin: 0;
  min-width: 10.5rem;
}

.lesson-ai-quiz__steps {
  order: 1;
  direction: rtl;
}

.lesson-ai-quiz__step {
  min-width: 5.7rem;
}

@media (max-width: 760px) {
  .lesson-ai-quiz__header {
    padding-inline-end: 2.8rem;
  }

  .lesson-ai-quiz__footer {
    flex-direction: column;
    align-items: stretch;
  }

  .lesson-ai-quiz__submit,
  .lesson-ai-quiz__steps {
    width: 100%;
  }

  .lesson-ai-quiz__submit {
    min-width: 0;
  }

  .lesson-ai-quiz__steps>* {
    flex: 1 1 0;
  }
}

.lesson-skeleton__sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Skeleton geometry mirrors the real .doc-toc rail on desktop and the
   same compact flow on phones; the actual ToC stylesheet takes over once
   lesson data is painted. */
.lesson-skeleton__toc {
  box-sizing: border-box;
  max-height: 70vh;
  overflow: hidden;
}

.lesson-skeleton__toc-toggle {
  display: none;
}

@media (max-width: 768px) {
  .lesson-view--loading {
    padding-bottom: calc(5rem + var(--bottom-nav-height, 54px));
  }

  .lesson-skeleton__content {
    width: 100%;
  }

  .lesson-skeleton__toc {
    display: none;
  }

  .lesson-skeleton__toc-toggle {
    position: fixed;
    inset-inline-start: 1rem;
    inset-block-end: calc(1rem + var(--bottom-nav-height, 54px));
    z-index: 40;
    display: grid;
    width: 2.9rem;
    height: 2.9rem;
    place-items: center;
    border: 1px solid var(--border-color, rgba(127, 127, 127, .25));
    border-radius: 50%;
    background: var(--color-surface, var(--color-bg, #fff));
    box-shadow: 0 10px 26px rgba(0, 0, 0, .18);
  }

  .lesson-skeleton__toc-toggle::before,
  .lesson-skeleton__toc-toggle::after,
  .lesson-skeleton__toc-toggle i {
    content: "";
    display: block;
    width: 1rem;
    height: .11rem;
    border-radius: 999px;
    background: var(--color-text-secondary, #8a8f98);
    box-shadow: 0 .28rem 0 var(--color-text-secondary, #8a8f98), 0 -.28rem 0 var(--color-text-secondary, #8a8f98);
  }
}


/* ── Lesson reader header — compact two-row control bar ───────────────────── */
/* ── Lesson reader header — dynamic bilingual hero & controls ─────────────── */
.lesson-view--reader .lesson-view__header {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
  min-height: 0;
  margin: 0 0 1.5rem;
  padding: 1.25rem 1.35rem 1.15rem;
  overflow: visible;
  border: 1px solid color-mix(in srgb, var(--color-primary) 18%, var(--color-border));
  border-radius: 20px;
  background: linear-gradient(
    145deg,
    color-mix(in srgb, var(--color-primary) 6%, var(--color-surface, Canvas)) 0%,
    var(--color-surface, Canvas) 65%
  );
  box-shadow:
    0 1px 3px rgb(0 0 0 / .04),
    0 10px 28px rgb(0 0 0 / .05);
  isolation: isolate;
  z-index: 30;
  transition: border-color .2s ease, box-shadow .2s ease;
}

.lesson-view--reader .lesson-view__header:hover {
  border-color: color-mix(in srgb, var(--color-primary) 32%, var(--color-border));
  box-shadow:
    0 2px 6px rgb(0 0 0 / .05),
    0 14px 36px rgb(0 0 0 / .08);
}

/* Directional glowing accent bar on the leading edge (right for RTL, left for LTR) */
.lesson-view--reader .lesson-view__header::before {
  content: "";
  position: absolute;
  inset-block: 16px;
  inset-inline-start: 0;
  width: 4px;
  border-radius: 999px;
  background: linear-gradient(180deg, var(--color-primary), color-mix(in srgb, var(--color-primary) 40%, transparent));
  box-shadow: 0 0 12px color-mix(in srgb, var(--color-primary) 50%, transparent);
}

/* ── Tier 1: Topline with badges & metadata ────────────────────────────────── */
.lesson-view--reader .lesson-view__header-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
  min-width: 0;
  flex-wrap: wrap;
}

.lesson-view--reader .lesson-view__header-badges {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .55rem;
  min-width: 0;
}

.lesson-view--reader .lesson-view__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .42rem;
  flex: 0 0 auto;
  margin: 0;
  padding: .2rem .65rem .2rem .22rem;
  border-radius: 999px;
  background: color-mix(in srgb, var(--color-primary) 12%, transparent);
  border: 1px solid color-mix(in srgb, var(--color-primary) 28%, var(--color-border));
  color: var(--color-primary);
  font-size: .8rem;
  font-weight: 800;
  line-height: 1;
}

.lesson-view--reader .lesson-view__header--ltr .lesson-view__eyebrow {
  padding: .2rem .22rem .2rem .65rem;
  text-transform: uppercase;
  letter-spacing: .06em;
  font-size: .74rem;
}

.lesson-view--reader .lesson-view__eyebrow-icon {
  display: grid;
  place-items: center;
  width: 1.55rem;
  height: 1.55rem;
  border-radius: 999px;
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 2px 6px color-mix(in srgb, var(--color-primary) 35%, transparent);
}

.lesson-view--reader .lesson-view__eyebrow-icon .lesson-icon {
  width: .88rem;
  height: .88rem;
  stroke-width: 2.2;
}

.lesson-view--reader .lesson-view__meta {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  flex-wrap: wrap;
  gap: .4rem;
  min-width: 0;
}

.lesson-view--reader .lesson-view__meta-item {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  min-height: 28px;
  padding: .18rem .62rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: var(--color-background-secondary, var(--color-surface));
  color: var(--color-text-secondary);
  font-size: .76rem;
  font-weight: 650;
  line-height: 1;
  white-space: nowrap;
  transition: background .15s ease, border-color .15s ease, color .15s ease;
}

.lesson-view--reader .lesson-view__meta-item:hover {
  border-color: color-mix(in srgb, var(--color-primary) 35%, var(--color-border));
  color: var(--color-text-primary);
}

.lesson-view--reader .lesson-view__meta-item-icon {
  display: grid;
  place-items: center;
  color: var(--color-primary);
}

.lesson-view--reader .lesson-view__meta-item-icon .lesson-icon {
  width: .85rem;
  height: .85rem;
}

.lesson-view--reader .lesson-view__meta-item--quiz {
  border-color: color-mix(in srgb, #f59e0b 35%, var(--color-border));
  background: color-mix(in srgb, #f59e0b 8%, var(--color-surface));
  color: #b45309;
}

[data-theme="dark"] .lesson-view--reader .lesson-view__meta-item--quiz {
  color: #fbbf24;
  background: color-mix(in srgb, #f59e0b 14%, var(--color-surface));
}

.lesson-view--reader .lesson-view__meta-item--quiz .lesson-icon {
  color: #f59e0b;
}

/* ── Tier 2: Hero title & description ──────────────────────────────────────── */
.lesson-view--reader .lesson-view__heading {
  flex: 0 0 auto;
  width: 100%;
  min-width: 0;
  margin: 0;
  text-align: start;
  display: flex;
  flex-direction: column;
  gap: .45rem;
}

.lesson-view--reader .lesson-view__title {
  width: 100%;
  max-width: 100%;
  margin: 0;
  color: var(--color-text-primary);
  font-size: clamp(1.42rem, 3.1vw, 2.15rem);
  font-weight: 850;
  line-height: 1.25;
  letter-spacing: -.02em;
  text-align: start;
  text-wrap: balance;
  word-break: break-word;
}

.lesson-view--reader .lesson-view__header--ltr .lesson-view__title {
  font-family: var(--font-english, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Inter", sans-serif);
  letter-spacing: -.028em;
  line-height: 1.22;
}

.lesson-view--reader .lesson-view__header--ar .lesson-view__title {
  font-family: inherit;
  letter-spacing: normal;
  line-height: 1.35;
}

.lesson-view--reader .lesson-view__title[dir="rtl"] {
  text-align: right;
}

.lesson-view--reader .lesson-view__title[dir="ltr"] {
  text-align: left;
}

.lesson-view--reader .lesson-view__description {
  max-width: 68rem;
  margin: 0;
  color: var(--color-text-secondary);
  font-size: clamp(.92rem, 1.4vw, 1.04rem);
  line-height: 1.65;
  text-align: start;
  word-break: break-word;
}

/* ── Tier 3: Controls toolbar & assistant guidance ─────────────────────────── */
.lesson-view--reader .lesson-view__header-footer {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  padding-top: .85rem;
  border-top: 1px solid color-mix(in srgb, var(--color-border) 75%, transparent);
}

.lesson-view--reader .lesson-view__subtitle-wrap {
  display: flex;
  align-items: center;
  gap: .5rem;
  min-width: 0;
  flex: 1 1 20rem;
}

.lesson-view--reader .lesson-view__subtitle-icon {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 999px;
  background: color-mix(in srgb, var(--color-primary) 12%, transparent);
  color: var(--color-primary);
}

.lesson-view--reader .lesson-view__subtitle-icon .lesson-icon {
  width: .85rem;
  height: .85rem;
}

.lesson-view--reader .lesson-view__subtitle {
  margin: 0;
  color: var(--color-text-secondary);
  font-size: .82rem;
  line-height: 1.5;
  text-align: start;
}

.lesson-view--reader .lesson-view__header-actions {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  flex-wrap: wrap;
  gap: .5rem;
  min-width: 0;
  padding-top: 0;
  border-top: none;
  overflow: visible;
  flex: 0 0 auto;
}

.lesson-view--reader .lesson-header__action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .45rem;
  flex: 0 0 auto;
  min-width: 0;
  min-height: 38px;
  padding: .45rem .82rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-surface, Canvas);
  color: var(--color-text-primary);
  font: inherit;
  font-size: .8rem;
  font-weight: 700;
  line-height: 1.2;
  white-space: nowrap;
  cursor: pointer;
  transition: background .16s ease, border-color .16s ease, color .16s ease, transform .16s ease, box-shadow .16s ease;
}

.lesson-view--reader .lesson-header__action:hover {
  border-color: color-mix(in srgb, var(--color-primary) 48%, var(--color-border));
  background: color-mix(in srgb, var(--color-primary) 9%, var(--color-surface));
  color: var(--color-primary);
  
  box-shadow: 0 3px 8px rgb(0 0 0 / .06);
}

.lesson-view--reader .lesson-header__action:active {
  transform: translateY(0);
}

.lesson-view--reader .lesson-header__action:focus-visible {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

.lesson-view--reader .lesson-header__action .lesson-icon {
  width: 1rem;
  height: 1rem;
  flex: 0 0 auto;
}

.lesson-view--reader .lesson-view__info-btn {
  border-color: var(--color-primary);
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 4px 14px color-mix(in srgb, var(--color-primary) 28%, transparent);
}

.lesson-view--reader .lesson-view__info-btn:hover {
  border-color: var(--color-primary-hover, var(--color-primary));
  background: var(--color-primary-hover, var(--color-primary));
  color: #fff;
  box-shadow: 0 6px 18px color-mix(in srgb, var(--color-primary) 38%, transparent);
}

.lesson-view--reader .lesson-reset-all {
  background: transparent;
  color: var(--color-text-secondary);
}

.lesson-view--reader .lesson-reset-all:hover {
  border-color: color-mix(in srgb, #ef4444 40%, var(--color-border));
  color: #ef4444;
  background: color-mix(in srgb, #ef4444 8%, transparent);
}

.lesson-view--reader .lesson-prefs,
.lesson-view--reader .lesson-bookmarks {
  position: relative;
  flex: 0 0 auto;
  min-width: 0;
}

.lesson-view--reader .lesson-prefs__toggle,
.lesson-view--reader .lesson-bookmarks__toggle {
  border-color: var(--color-border);
  background: var(--color-surface, Canvas);
  color: var(--color-text-primary);
}

.lesson-view--reader .lesson-prefs__toggle[aria-expanded="true"],
.lesson-view--reader .lesson-bookmarks__toggle[aria-expanded="true"] {
  border-color: var(--color-primary);
  background: color-mix(in srgb, var(--color-primary) 10%, var(--color-surface));
  color: var(--color-primary);
}

.lesson-view--reader .lesson-prefs__panel,
.lesson-view--reader .lesson-bookmarks__panel {
  z-index: 1000;
  max-width: min(340px, calc(100vw - 1rem));
  border-color: var(--color-border);
  border-radius: .85rem;
  background: var(--color-surface, Canvas);
  box-shadow: 0 18px 44px rgb(0 0 0 / .16);
}

.lesson-view--reader .lesson-prefs__panel {
  min-width: 250px;
}

.lesson-view--reader .lesson-bookmarks__panel {
  width: min(22rem, calc(100vw - 1rem));
}


/* ── Responsive Refinements ────────────────────────────────────────────────── */
@media (max-width: 768px) {
  .lesson-view--reader .lesson-view__header {
    gap: .85rem;
    padding: 1rem 1rem .95rem;
    border-radius: 16px;
    margin-bottom: 1.25rem;
  }

  .lesson-view--reader .lesson-view__title {
    font-size: clamp(1.28rem, 5.2vw, 1.65rem);
  }

  .lesson-view--reader .lesson-view__subtitle {
    font-size: .78rem;
  }

  .lesson-view--reader .lesson-view__header-footer {
    flex-direction: column;
    align-items: stretch;
    gap: .75rem;
  }

  /* In a column footer, the row-oriented "flex: 1 1 20rem" turned into a
     320px-tall box — the big blank gap. Size to content instead. */
  .lesson-view--reader .lesson-view__subtitle-wrap {
    flex: 0 0 auto;
  }

  /* NOT overflow-x:auto — that also clips the absolutely positioned
     settings/bookmarks panels (and shows a sliver of scrollbar) so they never
     appear. The row already wraps (flex-wrap), so nothing needs scrolling. */
  .lesson-view--reader .lesson-view__header-actions {
    width: 100%;
    justify-content: flex-start;
    overflow: visible;
    padding-bottom: 2px;
  }

  /* On phones the panels open as a viewport-fitted sheet above the bottom bar
     instead of hanging off their (possibly off-centre) toggle button. */
  .lesson-view--reader .lesson-prefs__panel,
  .lesson-view--reader .lesson-bookmarks__panel {
    position: fixed;
    inset-inline: .5rem;
    top: auto;
    bottom: calc(5.5rem + env(safe-area-inset-bottom, 0px));
    width: auto;
    min-width: 0;
    max-width: none;
    max-height: min(60vh, 28rem);
    overflow-y: auto;
  }
}

@media (max-width: 480px) {
  .lesson-view--reader .lesson-view__header {
    padding: .85rem .85rem .9rem;
    border-radius: 14px;
  }

  .lesson-view--reader .lesson-header__action {
    padding: .4rem .6rem;
    font-size: .76rem;
  }

  .lesson-view--reader .lesson-header__action-label {
    display: inline;
  }
}

@media (max-width: 400px) {
  .lesson-view--reader .lesson-view__meta-item {
    font-size: .68rem;
    padding: .15rem .5rem;
  }

  .lesson-view--reader .lesson-header__action {
    width: 38px;
    min-width: 38px;
    padding-inline: 0;
  }

  .lesson-view--reader .lesson-header__action-label {
    display: none;
  }
}

/* The inline first-paint skeleton should occupy the same geometry as the
   JavaScript-rendered loading skeleton, with no delayed "flash" transition. */
.lesson-view--initial-skeleton {
  min-height: min(72vh, 760px);
}

.lesson-view--initial-skeleton .lesson-skeleton__header {
  min-height: 86px;
}

.lesson-view--initial-skeleton .lesson-skeleton__layout {
  min-height: 480px;
}

@media (max-width: 760px) {
  .lesson-view--initial-skeleton .lesson-skeleton__layout {
    min-height: 360px;
  }
}

/* Keep the three selection actions comfortably tappable on narrow screens. */
.lesson-selection-popup__btn {
  min-height: 38px;
}

@media (max-width: 520px) {
  .lesson-selection-popup {
    gap: .3rem;
    max-width: calc(100vw - 16px);
  }

  .lesson-selection-popup__btn {
    flex: 1 1 auto;
    min-width: 0;
    padding-inline: .6rem;
    font-size: .8rem;
  }
}


/* ── Embedded quiz/lesson references ─────────────────────────────────────── */
.lesson-ref-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  border: 1px solid var(--color-border);
  border-radius: 16px;
  background: color-mix(in srgb, var(--color-surface) 88%, transparent);
  box-shadow: var(--shadow-sm, 0 4px 16px rgba(0, 0, 0, .06));
  overflow: hidden;
}

.lesson-ref-card__main {
  display: flex;
  gap: .8rem;
  min-width: 0;
  align-items: flex-start;
}

.lesson-ref-card__icon {
  width: 42px;
  height: 42px;
  flex: 0 0 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.lesson-ref-card--lesson .lesson-ref-card__icon {
  background: color-mix(in srgb, var(--color-success) 14%, var(--color-surface));
  color: var(--color-success);
}

.lesson-ref-card__icon svg {
  width: 21px;
  height: 21px;
}

.lesson-ref-card__copy {
  min-width: 0;
}

.lesson-ref-card__label,
.lesson-ref-card__count {
  display: block;
  color: var(--color-text-secondary);
  font-size: .78rem;
}

.lesson-ref-card__title {
  margin: .18rem 0;
  font-size: 1rem;
  overflow-wrap: anywhere;
}

.lesson-ref-card__description,
.lesson-ref-card__unavailable {
  margin: .2rem 0 0;
  color: var(--color-text-secondary);
  font-size: .84rem;
  line-height: 1.5;
}

.lesson-ref-card__protected {
  display: inline-flex;
  align-items: center;
  gap: .25rem;
  margin-top: .35rem;
  color: var(--color-warning, #b45309);
  font-size: .78rem;
}

.lesson-ref-card__protected svg {
  width: 14px;
  height: 14px;
}

.lesson-ref-card__actions {
  display: grid;
  grid-template-columns: repeat(4, minmax(72px, auto));
  gap: .4rem;
  align-self: stretch;
  align-items: center;
}

.lesson-ref-card__action {
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .35rem;
  padding: .45rem .55rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: transparent;
  color: var(--color-text-primary);
  font: inherit;
  font-size: .8rem;
  cursor: pointer;
  white-space: nowrap;
}

.lesson-ref-card__action:hover:not(:disabled) {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.lesson-ref-card__action:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.lesson-ref-card__action svg {
  width: 16px;
  height: 16px;
  flex: 0 0 16px;
}

.lesson-ref-card__action:disabled {
  opacity: .45;
  cursor: not-allowed;
}

.lesson-ref-card.is-unavailable .lesson-ref-card__action--start,
.lesson-ref-card.is-unavailable .lesson-ref-card__action--download,
.lesson-ref-card.is-unavailable .lesson-ref-card__action--ask {
  pointer-events: none;
}

/* ── Lesson password gate ────────────────────────────────────────────────── */
.lesson-password-dialog {
  border: 0;
  padding: 0;
  background: transparent;
  color: var(--color-text-primary);
  width: min(92vw, 460px);
  max-width: 460px;
}

.lesson-password-dialog::backdrop {
  background: rgba(15, 23, 42, .72);
  backdrop-filter: blur(6px);
}

.lesson-password-dialog__panel {
  display: grid;
  gap: .75rem;
  padding: 1.2rem;
  border: 1px solid var(--color-border);
  border-radius: 18px;
  background: var(--color-surface);
  box-shadow: var(--shadow-lg, 0 20px 60px rgba(0, 0, 0, .22));
}

.lesson-password-dialog__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: .75rem;
}

.lesson-password-dialog__eyebrow {
  color: var(--color-warning, #b45309);
  font-size: .75rem;
  font-weight: 700;
}

.lesson-password-dialog__header h2 {
  margin: .2rem 0 0;
  font-size: 1.1rem;
}

.lesson-password-dialog__close {
  width: 40px;
  height: 40px;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: transparent;
  color: inherit;
  cursor: pointer;
  font-size: 1.25rem;
}

.lesson-password-dialog__message,
.lesson-password-dialog__error {
  margin: 0;
  color: var(--color-text-secondary);
  font-size: .86rem;
}

.lesson-password-dialog__error {
  color: var(--color-error, #dc2626);
}

.lesson-password-dialog__label {
  font-weight: 700;
  font-size: .84rem;
}

.lesson-password-dialog__field {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: .45rem;
}

.lesson-password-dialog__field input {
  min-height: 42px;
  width: 100%;
  min-width: 0;
  padding: .55rem .65rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: transparent;
  color: inherit;
  font: inherit;
}

.lesson-password-dialog__toggle {
  min-width: 52px;
  min-height: 42px;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: transparent;
  color: inherit;
  font: inherit;
  cursor: pointer;
}

.lesson-password-dialog__actions {
  display: flex;
  justify-content: flex-end;
  gap: .5rem;
  flex-wrap: wrap;
  margin-top: .2rem;
}

@media (max-width: 760px) {
  .lesson-ref-card {
    grid-template-columns: 1fr;
  }

  .lesson-ref-card__actions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    width: 100%;
  }

  .lesson-ref-card__action {
    min-width: 0;
  }
}

@media (max-width: 420px) {
  .lesson-ref-card__main {
    gap: .55rem;
  }

  .lesson-ref-card {
    padding: .8rem;
  }
}

@media (prefers-reduced-motion: reduce) {

  .lesson-ref-card,
  .lesson-password-dialog__panel {
    scroll-behavior: auto;
  }
}

/* Embedded questions follow the quiz page's answer/check/review rhythm. */
.lesson-view .lesson-question {
  margin-block: 1.4rem;
  padding: clamp(1rem, 2.6vw, 1.4rem);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  background: var(--color-surface, Canvas);
  box-shadow: 0 8px 24px rgb(0 0 0 / .045);
}

.lesson-question__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .75rem;
  margin-bottom: 1rem;
}

.lesson-question__number,
.lesson-question__type {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: .25rem .65rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: .76rem;
  font-weight: 750;
}

.lesson-question__number {
  background: var(--color-primary-light, rgba(99, 102, 241, .10));
  border-color: color-mix(in srgb, var(--color-primary) 28%, var(--color-border));
  color: var(--color-primary);
}

.lesson-question__type {
  color: var(--color-text-secondary);
}

.lesson-question__prompt {
  margin-block: 0 1rem;
  color: var(--color-text-primary);
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.75;
}

.lesson-question__options {
  display: grid;
  gap: .65rem;
  margin: 0;
}

.lesson-question__option {
  display: flex;
  align-items: flex-start;
  gap: .75rem;
  width: 100%;
  padding: .8rem .9rem;
  border: 1px solid var(--color-border);
  border-radius: 11px;
  background: var(--color-surface, Canvas);
  color: var(--color-text-primary);
  font: inherit;
  line-height: 1.6;
  text-align: start;
  cursor: pointer;
  transition: border-color .16s ease, background .16s ease, transform .16s ease;
}

.lesson-question__option:hover:not(:disabled) {
  border-color: color-mix(in srgb, var(--color-primary) 55%, var(--color-border));
  
}

.lesson-question__option:focus-visible,
.lesson-question__check-btn:focus-visible,
.lesson-question__essay-check-btn:focus-visible {
  outline: 2px solid var(--color-focus-ring, var(--color-primary));
  outline-offset: 2px;
}

.lesson-question__option-marker {
  display: grid;
  flex: 0 0 1.55rem;
  width: 1.55rem;
  height: 1.55rem;
  place-items: center;
  border: 1px solid var(--color-border);
  border-radius: 50%;
  color: var(--color-text-secondary);
  font-size: .72rem;
  font-weight: 800;
  line-height: 1;
}

.lesson-question__option-text {
  min-width: 0;
}

.lesson-question__option.is-selected {
  border-color: var(--color-primary);
  background: var(--color-primary-light, rgba(99, 102, 241, .10));
}

.lesson-question__option.is-selected .lesson-question__option-marker {
  border-color: var(--color-primary);
  background: var(--color-primary);
  color: #fff;
}

.lesson-question[data-multi-select="true"] .lesson-question__option-marker {
  border-radius: .4rem;
}

.lesson-question__option.is-correct {
  border-color: #16a34a;
  background: rgb(34 197 94 / .10);
}

.lesson-question__option.is-correct .lesson-question__option-marker {
  border-color: #16a34a;
  background: #16a34a;
  color: #fff;
}

.lesson-question__option.is-wrong {
  border-color: #dc2626;
  background: rgb(239 68 68 / .09);
}

.lesson-question__option:disabled {
  cursor: default;
}

.lesson-question__check-btn,
.lesson-question__essay-check-btn {
  min-height: 42px;
  margin-top: .9rem;
  padding: .55rem 1.05rem;
  border: 1px solid var(--color-primary);
  border-radius: 9px;
  background: var(--color-primary);
  color: #fff;
  font: inherit;
  font-weight: 750;
  cursor: pointer;
  transition: opacity .16s ease, transform .16s ease;
}

.lesson-question__check-btn:hover:not(:disabled),
.lesson-question__essay-check-btn:hover:not(:disabled) { filter: brightness(1.07); }

.lesson-question__check-btn:disabled,
.lesson-question__essay-check-btn:disabled {
  opacity: .48;
  cursor: not-allowed;
}

.lesson-question__feedback {
  display: grid;
  gap: .55rem;
  margin-top: 1rem;
  padding: .9rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 11px;
  background: var(--color-background-secondary, var(--color-surface));
}

.lesson-question__feedback[hidden] {
  display: none;
}

.lesson-question__verdict {
  color: var(--color-text-primary);
  font-weight: 800;
}

.lesson-question__verdict.is-correct {
  color: #15803d;
}

.lesson-question__verdict.is-wrong {
  color: #b91c1c;
}

.lesson-question__correct-answer,
.lesson-question__explanation,
.lesson-question__model-answer {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.lesson-question__essay-wrap {
  display: grid;
  gap: .45rem;
  color: var(--color-text-secondary);
  font-size: .82rem;
  font-weight: 750;
}

.lesson-question__essay-input {
  margin: 0;
  padding: .8rem .9rem;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-surface, Canvas);
  color: var(--color-text-primary);
  line-height: 1.6;
}

.lesson-question__essay-input:focus-visible {
  border-color: var(--color-primary);
  outline: 2px solid color-mix(in srgb, var(--color-primary) 30%, transparent);
  outline-offset: 1px;
}

.lesson-question__essay-rating {
  color: #b7791f;
  font-size: 1.05rem;
  font-weight: 850;
  letter-spacing: .04em;
}

.lesson-question__model-answer {
  padding-top: .55rem;
  border-top: 1px solid var(--color-border);
}

@media (max-width: 520px) {
  .lesson-question__header {
    align-items: flex-start;
    flex-direction: column;
    gap: .45rem;
  }

  .lesson-question__check-btn,
  .lesson-question__essay-check-btn {
    width: 100%;
  }
}

/* ── Lesson community: polished discussion surface ───────────────────────── */
.lesson-comments {
  --community-accent: var(--color-primary, #5791ff);
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(1.1rem, 3.2vw, 2rem);
  border: 1px solid color-mix(in srgb, var(--community-accent) 24%, var(--color-border));
  border-radius: 26px;
  background:
    radial-gradient(ellipse at 100% 0, color-mix(in srgb, var(--community-accent) 12%, transparent), transparent 40%),
    linear-gradient(145deg, color-mix(in srgb, var(--color-surface) 97%, #111b2d), var(--color-surface));
  box-shadow: 0 22px 60px rgb(0 0 0 / .14), inset 0 1px rgb(255 255 255 / .035);
}

.lesson-comments::before {
  position: absolute;
  z-index: -1;
  inset: 0 0 auto;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--community-accent), #38c8b2, transparent);
  content: "";
}

.lesson-comments__ambient {
  position: absolute;
  z-index: -1;
  top: -110px;
  inset-inline-end: -90px;
  width: 260px;
  height: 260px;
  border-radius: 50%;
  background: color-mix(in srgb, var(--community-accent) 11%, transparent);
  filter: blur(54px);
  pointer-events: none;
}

.lesson-comments__head {
  align-items: center;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid color-mix(in srgb, var(--color-border) 76%, transparent);
}

.lesson-comments__identity {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-width: 0;
}

.lesson-comments__mark,
.lesson-comments__composer-mark {
  display: grid;
  flex: 0 0 auto;
  place-items: center;
  width: 54px;
  height: 54px;
  border: 1px solid color-mix(in srgb, var(--community-accent) 28%, var(--color-border));
  border-radius: 17px;
  background: linear-gradient(145deg, color-mix(in srgb, var(--community-accent) 18%, var(--color-surface)), color-mix(in srgb, var(--community-accent) 6%, var(--color-surface)));
  color: var(--community-accent);
  box-shadow: inset 0 1px rgb(255 255 255 / .08), 0 8px 22px color-mix(in srgb, var(--community-accent) 9%, transparent);
}

.lesson-comments__mark svg {
  width: 25px;
  height: 25px;
  stroke: currentColor;
  stroke-width: 1.65;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.lesson-comments__heading-copy {
  display: grid;
  gap: .25rem;
  min-width: 0;
}

.lesson-comments__eyebrow {
  color: var(--community-accent);
  font-size: .69rem;
  font-weight: 800;
  letter-spacing: .04em;
}

.lesson-comments__heading-copy h2 {
  margin: 0;
  color: var(--color-text-primary);
  font-size: clamp(1.25rem, 2.5vw, 1.65rem);
  font-weight: 850;
  line-height: 1.3;
}

.lesson-comments__heading-copy p {
  margin: 0;
  color: var(--color-text-secondary);
  font-size: .83rem;
  line-height: 1.6;
}

.lesson-comments__stat {
  display: grid;
  justify-items: center;
  gap: .12rem;
  min-width: 84px;
  padding: .65rem .85rem;
  border: 1px solid color-mix(in srgb, var(--community-accent) 20%, var(--color-border));
  border-radius: 15px;
  background: color-mix(in srgb, var(--community-accent) 6%, var(--color-surface));
}

.lesson-comments__stat strong {
  color: var(--community-accent);
  font-size: 1.15rem;
  font-weight: 850;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.lesson-comments__stat span {
  color: var(--color-text-secondary);
  font-size: .62rem;
  white-space: nowrap;
}

.lesson-comments__toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .8rem;
  margin-top: 1.1rem;
}

.lesson-comments__toolbar-label {
  color: var(--color-text-tertiary, var(--color-text-secondary));
  font-size: .74rem;
  font-weight: 700;
}

.lesson-comments__sort {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem;
  padding: 4px;
  border: 1px solid color-mix(in srgb, var(--color-border) 78%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--color-surface) 78%, var(--color-background-secondary, #111));
}

.lesson-comments__sort-btn {
  min-height: 34px;
  padding: .4rem .8rem;
  border: 1px solid transparent;
  border-radius: 999px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: .76rem;
  font-weight: 650;
  cursor: pointer;
  transition: background .16s ease, color .16s ease, border-color .16s ease, box-shadow .16s ease;
}

.lesson-comments__sort-btn:hover {
  color: var(--color-text-primary);
  border-color: color-mix(in srgb, var(--community-accent) 25%, transparent);
}

.lesson-comments__sort-btn:focus-visible,
.lesson-comments__more:focus-visible,
.lesson-comment__react:focus-visible,
.lesson-comment__link:focus-visible {
  outline: 2px solid var(--community-accent);
  outline-offset: 2px;
}

.lesson-comments__sort-btn.is-active {
  border-color: color-mix(in srgb, var(--community-accent) 55%, transparent);
  background: linear-gradient(135deg, var(--community-accent), color-mix(in srgb, var(--community-accent) 74%, #8d7aff));
  color: #fff;
  box-shadow: 0 4px 12px color-mix(in srgb, var(--community-accent) 26%, transparent);
}

.lesson-comments__notice {
  display: flex;
  align-items: center;
  gap: .65rem;
  margin-top: 1rem;
  padding: .72rem .85rem;
  border: 1px solid color-mix(in srgb, #36b991 22%, var(--color-border));
  border-radius: 13px;
  background: color-mix(in srgb, #36b991 7%, var(--color-surface));
  color: var(--color-text-secondary);
  font-size: .74rem;
  line-height: 1.55;
}

.lesson-comments__notice-icon {
  display: grid;
  flex: 0 0 27px;
  place-items: center;
  width: 27px;
  height: 27px;
  border-radius: 9px;
  background: color-mix(in srgb, #36b991 13%, var(--color-surface));
  color: #36b991;
}

.lesson-comments__notice-icon svg {
  width: 16px;
  height: 16px;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.lesson-comments__list {
  display: grid;
  gap: .8rem;
  margin: 1.1rem 0 .8rem;
}

.lesson-comment {
  position: relative;
  overflow: visible;
  padding: 1rem 1.05rem .85rem;
  border: 1px solid color-mix(in srgb, var(--color-border) 82%, transparent);
  border-radius: 17px;
  background: linear-gradient(145deg, color-mix(in srgb, var(--color-surface) 97%, var(--community-accent)), var(--color-surface));
  box-shadow: 0 5px 16px rgb(0 0 0 / .045), inset 0 1px rgb(255 255 255 / .025);
  scroll-margin-top: 5rem;
  transition: border-color .2s ease, box-shadow .2s ease, transform .2s ease;
}

.lesson-comment:hover {
  border-color: color-mix(in srgb, var(--community-accent) 24%, var(--color-border));
  box-shadow: 0 9px 24px rgb(0 0 0 / .08), inset 0 1px rgb(255 255 255 / .035);
}

.lesson-comment--highlighted {
  border-color: var(--community-accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--community-accent) 20%, transparent), 0 12px 32px rgb(0 0 0 / .1);
}

.lesson-comment__meta {
  display: flex;
  align-items: center;
  gap: .65rem;
  min-width: 0;
}

.lesson-comment__avatar {
  display: grid;
  flex: 0 0 39px;
  place-items: center;
  width: 39px;
  height: 39px;
  border: 1px solid color-mix(in srgb, var(--community-accent) 26%, transparent);
  border-radius: 13px;
  background: linear-gradient(145deg, color-mix(in srgb, var(--community-accent) 22%, var(--color-surface)), color-mix(in srgb, var(--community-accent) 8%, var(--color-surface)));
  color: var(--community-accent);
  font-size: .92rem;
  font-weight: 850;
}

.lesson-comment__avatar--1 { --avatar-hue: #3dbf9b; background: color-mix(in srgb, var(--avatar-hue) 15%, var(--color-surface)); color: var(--avatar-hue); border-color: color-mix(in srgb, var(--avatar-hue) 30%, var(--color-border)); }
.lesson-comment__avatar--2 { --avatar-hue: #ed9d4b; background: color-mix(in srgb, var(--avatar-hue) 15%, var(--color-surface)); color: var(--avatar-hue); border-color: color-mix(in srgb, var(--avatar-hue) 30%, var(--color-border)); }
.lesson-comment__avatar--3 { --avatar-hue: #da71a7; background: color-mix(in srgb, var(--avatar-hue) 15%, var(--color-surface)); color: var(--avatar-hue); border-color: color-mix(in srgb, var(--avatar-hue) 30%, var(--color-border)); }
.lesson-comment__avatar--4 { --avatar-hue: #50a8c9; background: color-mix(in srgb, var(--avatar-hue) 15%, var(--color-surface)); color: var(--avatar-hue); border-color: color-mix(in srgb, var(--avatar-hue) 30%, var(--color-border)); }

.lesson-comment__author-wrap {
  display: grid;
  min-width: 0;
  gap: .12rem;
}

.lesson-comment__author-wrap strong {
  unicode-bidi: plaintext; /* truncate by the name's own direction */
  text-align: start;
  overflow: hidden;
  color: var(--color-text-primary);
  font-size: .84rem;
  font-weight: 800;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.lesson-comment__author-label {
  color: var(--color-text-tertiary, var(--color-text-secondary));
  font-size: .65rem;
}

.lesson-comment__meta time {
  margin-inline-start: auto;
  color: var(--color-text-tertiary, var(--color-text-secondary));
  font-size: .69rem;
  white-space: nowrap;
}

.lesson-comment__edited {
  padding: .2rem .45rem;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  color: var(--color-text-tertiary, var(--color-text-secondary));
  font-size: .6rem;
  white-space: nowrap;
}

.lesson-comment__body {
  margin: .9rem 0 .85rem;
  padding-inline-start: calc(39px + .65rem);
  color: var(--color-text-primary);
  font-size: .92rem;
  line-height: 1.85;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.lesson-comment__actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .35rem;
  margin: 0;
  padding-top: .65rem;
  border-top: 1px solid color-mix(in srgb, var(--color-border) 75%, transparent);
}

.lesson-comment__react,
.lesson-comment__link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .35rem;
  min-height: 32px;
  padding: .35rem .65rem;
  border: 1px solid transparent;
  border-radius: 9px;
  background: transparent;
  color: var(--color-text-secondary);
  font: inherit;
  font-size: .72rem;
  font-weight: 650;
  text-decoration: none;
  cursor: pointer;
  transition: background .15s ease, border-color .15s ease, color .15s ease;
}

.lesson-comment__react:hover,
.lesson-comment__link:hover {
  border-color: color-mix(in srgb, var(--community-accent) 22%, var(--color-border));
  background: color-mix(in srgb, var(--community-accent) 8%, var(--color-surface));
  color: var(--community-accent);
}
.lesson-comment__link.is-copied { color: #36b991; }

.lesson-comment__react.is-active {
  border-color: color-mix(in srgb, var(--community-accent) 30%, var(--color-border));
  background: color-mix(in srgb, var(--community-accent) 10%, var(--color-surface));
  color: var(--community-accent);
}

.lesson-comment__avatar-button {
  position: relative;
  display: grid;
  flex: 0 0 39px;
  place-items: center;
  width: 39px;
  height: 39px;
  padding: 0;
  overflow: visible;
  border: 0;
  border-radius: 50%;
  background: transparent;
  cursor: pointer;
}

.lesson-comment__author-identity { position: relative; display: inline-flex; flex: 0 0 auto; }
.lesson-comment__avatar-image { width: 39px; height: 39px; border: 1px solid color-mix(in srgb, var(--community-accent) 35%, var(--color-border)); border-radius: 50%; object-fit: cover; box-shadow: 0 3px 12px rgb(0 0 0 / .14); }
.lesson-comment__avatar-button:focus-visible { outline: 3px solid color-mix(in srgb, var(--community-accent) 50%, transparent); outline-offset: 3px; }
.lesson-comment__author-handle { color: var(--community-accent); font-size: .65rem; font-weight: 650; }
.lesson-comment__role-badge { padding: .22rem .48rem; border: 1px solid color-mix(in srgb, var(--community-accent) 30%, var(--color-border)); border-radius: 999px; background: color-mix(in srgb, var(--community-accent) 9%, var(--color-surface)); color: var(--community-accent); font-size: .58rem; font-weight: 800; white-space: nowrap; }

.lesson-comment__author-card {
  position: fixed;
  z-index: 10050;
  inset-block-end: auto;
  inset-inline-start: auto;
  display: grid;
  width: min(320px, calc(100vw - 24px));
  max-height: calc(100dvh - 24px);
  overflow-x: hidden;
  overflow-y: auto;
  border: 1px solid color-mix(in srgb, var(--community-accent) 28%, var(--color-border));
  border-radius: 17px;
  background: var(--color-surface);
  box-shadow: 0 18px 48px rgb(0 0 0 / .28), 0 0 0 1px rgb(255 255 255 / .035) inset;
  animation: lesson-author-card-in .16s ease-out both;
}
.lesson-comment__author-card[hidden] { display: none; }
.lesson-comment__author-cover { display: block; height: 88px; overflow: hidden; background: linear-gradient(125deg, color-mix(in srgb, var(--community-accent) 50%, #131a29), color-mix(in srgb, var(--community-accent) 8%, #23283a)); }
.lesson-comment__author-cover img { width: 100%; height: 100%; object-fit: cover; }
.lesson-comment__author-card-body { display: grid; justify-items: start; gap: .35rem; padding: .85rem 1rem 1rem; }
.lesson-comment__author-card-role { padding: .2rem .5rem; border-radius: 999px; background: color-mix(in srgb, var(--community-accent) 12%, var(--color-surface)); color: var(--community-accent); font-size: .61rem; font-weight: 800; }
.lesson-comment__author-card-body > strong { color: var(--color-text-primary); font-size: .96rem; font-weight: 850; }
.lesson-comment__author-card-handle { color: var(--community-accent); font-size: .75rem; font-weight: 700; }
.lesson-comment__author-card-bio { color: var(--color-text-secondary); font-size: .75rem; line-height: 1.7; }
.lesson-comment__author-profile-link { display: inline-flex; align-items: center; gap: .35rem; margin-top: .25rem; color: var(--community-accent); font-size: .73rem; font-weight: 800; text-decoration: none; }
.lesson-comment__author-profile-link:hover { text-decoration: underline; }
.lesson-comment__author-profile-link svg { width: 14px; height: 14px; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
@keyframes lesson-author-card-in { from { opacity: 0; transform: translateY(5px) scale(.98); } to { opacity: 1; transform: translateY(0) scale(1); } }

.lesson-comment__vote-group { display: inline-grid; justify-items: start; gap: .1rem; }
.lesson-comment__vote-buttons { display: inline-flex; align-items: center; gap: .2rem; }
.lesson-comment__react svg { width: 15px; height: 15px; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.lesson-comment__link svg { width: 14px; height: 14px; flex: 0 0 auto; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.lesson-comment__vote-group[aria-busy="true"] .lesson-comment__react { opacity: .72; }
.lesson-comment__ratio { display: grid; width: calc(100% - .5rem); gap: .2rem; padding-inline: .25rem; }
.lesson-comment__ratio-labels { display: flex; justify-content: space-between; color: var(--color-text-tertiary, var(--color-text-secondary)); font-size: .57rem; font-weight: 750; font-variant-numeric: tabular-nums; }
.lesson-comment__ratio-track { display: flex; height: 4px; overflow: hidden; border-radius: 999px; background: color-mix(in srgb, #e16d7b 24%, var(--color-surface)); }
.lesson-comment__ratio-like { display: block; height: 100%; background: linear-gradient(90deg, #38b98c, #56d8a5); transition: width .22s ease; }
.lesson-comment__ratio-dislike { display: block; height: 100%; background: linear-gradient(90deg, #ef8790, #d85d6d); }
.lesson-comments__success-note { margin: .7rem 0 0; padding: .65rem .8rem; border: 1px solid color-mix(in srgb, #38b98c 35%, var(--color-border)); border-radius: 11px; background: color-mix(in srgb, #38b98c 9%, var(--color-surface)); color: color-mix(in srgb, #38b98c 78%, var(--color-text-primary)); font-size: .75rem; }
.lesson-comments__error-note { margin: .7rem 0; padding: .7rem .85rem; border: 1px solid color-mix(in srgb, #e06c73 38%, var(--color-border)); border-radius: 12px; background: color-mix(in srgb, #e06c73 10%, var(--color-surface)); color: #e06c73; font-size: .78rem; line-height: 1.55; }

.lesson-comment__link--danger { color: #e06c73; }
.lesson-comment__link--danger:hover { border-color: color-mix(in srgb, #e06c73 28%, var(--color-border)); background: color-mix(in srgb, #e06c73 9%, var(--color-surface)); color: #e06c73; }

.lesson-comment__replies {
  display: grid;
  gap: .65rem;
  margin-top: .8rem;
  padding-inline-start: 1rem;
  border-inline-start: 2px solid color-mix(in srgb, var(--community-accent) 30%, var(--color-border));
}

.lesson-comment--reply {
  padding: .8rem;
  border-radius: 14px;
  background: color-mix(in srgb, var(--color-surface) 92%, var(--community-accent));
}

.lesson-comment--reply .lesson-comment__avatar { width: 32px; height: 32px; flex-basis: 32px; border-radius: 11px; font-size: .78rem; }
.lesson-comment--reply .lesson-comment__body { padding-inline-start: calc(32px + .65rem); font-size: .85rem; }

.lesson-comment__reply-slot:empty { margin: 0; }

.lesson-comments__pending-note {
  margin: .6rem 0;
  padding: .75rem .85rem;
  border: 1px solid color-mix(in srgb, #d59a3b 34%, var(--color-border));
  border-radius: 12px;
  background: color-mix(in srgb, #d59a3b 9%, var(--color-surface));
  color: color-mix(in srgb, #d59a3b 78%, var(--color-text-primary));
  font-size: .78rem;
  line-height: 1.6;
}

.lesson-comments__empty {
  display: grid;
  justify-items: center;
  gap: .5rem;
  padding: clamp(1.5rem, 4vw, 2.4rem) 1rem;
  border: 1px dashed color-mix(in srgb, var(--community-accent) 28%, var(--color-border));
  border-radius: 18px;
  background: color-mix(in srgb, var(--community-accent) 4%, var(--color-surface));
  text-align: center;
}

.lesson-comments__empty-mark {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  margin-bottom: .2rem;
  border: 1px solid color-mix(in srgb, var(--community-accent) 24%, var(--color-border));
  border-radius: 16px;
  background: color-mix(in srgb, var(--community-accent) 10%, var(--color-surface));
  color: var(--community-accent);
}

.lesson-comments__empty-mark svg { width: 23px; height: 23px; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.lesson-comments__empty strong { color: var(--color-text-primary); font-size: .95rem; font-weight: 800; }
.lesson-comments__empty > span:last-child { max-width: 390px; color: var(--color-text-secondary); font-size: .78rem; line-height: 1.65; }

.lesson-comments__skeleton {
  height: 112px;
  border: 1px solid var(--color-border);
  border-radius: 17px;
  background: linear-gradient(100deg, color-mix(in srgb, var(--color-surface) 94%, var(--color-border)) 20%, color-mix(in srgb, var(--community-accent) 10%, var(--color-surface)) 40%, color-mix(in srgb, var(--color-surface) 94%, var(--color-border)) 60%);
  background-size: 220% 100%;
  animation: lesson-comment-shimmer 1.6s ease infinite;
}

.lesson-comments__more {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: .45rem;
  margin: .6rem auto 0;
  padding: .6rem 1rem;
  border: 1px solid color-mix(in srgb, var(--community-accent) 28%, var(--color-border));
  border-radius: 999px;
  background: color-mix(in srgb, var(--community-accent) 6%, var(--color-surface));
  color: var(--community-accent);
  font: inherit;
  font-size: .77rem;
  font-weight: 750;
  cursor: pointer;
  transition: transform .15s ease, background .15s ease;
}

.lesson-comments__more:hover {  background: color-mix(in srgb, var(--community-accent) 12%, var(--color-surface)); }
.lesson-comments__more[hidden] { display: none; }

.lesson-comments__permalink-note {
  padding: .55rem .75rem;
  border-inline-start: 3px solid var(--community-accent);
  border-radius: 8px 12px 12px 8px;
  background: color-mix(in srgb, var(--community-accent) 7%, var(--color-surface));
  color: var(--color-text-secondary);
  font-size: .72rem;
}

.lesson-comments__composer {
  gap: .8rem;
  margin-top: 1.35rem;
  padding: 1rem;
  border: 1px solid color-mix(in srgb, var(--community-accent) 24%, var(--color-border));
  border-radius: 18px;
  background: linear-gradient(145deg, color-mix(in srgb, var(--community-accent) 7%, var(--color-surface)), color-mix(in srgb, var(--color-surface) 97%, #101827));
  box-shadow: inset 0 1px rgb(255 255 255 / .035);
}

.lesson-comments__composer-head {
  display: flex;
  align-items: center;
  gap: .7rem;
}

.lesson-comments__composer-mark {
  width: 38px;
  height: 38px;
  border-radius: 12px;
}

.lesson-comments__composer-mark svg { width: 18px; height: 18px; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.lesson-comments__composer-head label { display: block; color: var(--color-text-primary); font-size: .88rem; font-weight: 800; cursor: text; }
.lesson-comments__composer-head p { margin: .1rem 0 0; color: var(--color-text-secondary); font-size: .69rem; }

.lesson-comments__composer textarea,
.lesson-comments__form--reply textarea,
.lesson-comment__edit-form textarea {
  display: block;
  box-sizing: border-box;
  width: 100%;
  min-height: 44px;
  max-height: 180px;
  padding: .85rem .95rem;
  border: 1px solid color-mix(in srgb, var(--color-border) 85%, transparent);
  border-radius: 13px;
  background: color-mix(in srgb, var(--color-surface) 94%, transparent);
  color: var(--color-text-primary);
  font: inherit;
  font-size: .84rem;
  line-height: 1.7;
  resize: none;
  transition: border-color .15s ease, box-shadow .15s ease, background .15s ease;
}

.lesson-comments__composer textarea::placeholder,
.lesson-comments__form--reply textarea::placeholder { color: var(--color-text-tertiary, var(--color-text-secondary)); opacity: .8; }

.lesson-comments__composer textarea:focus-visible,
.lesson-comments__form--reply textarea:focus-visible,
.lesson-comment__edit-form textarea:focus-visible {
  border-color: color-mix(in srgb, var(--community-accent) 70%, var(--color-border));
  outline: none;
  background: var(--color-surface);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--community-accent) 15%, transparent);
}

.lesson-comments__form-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: .7rem;
}

.lesson-comments__count {
  color: var(--color-text-tertiary, var(--color-text-secondary));
  font-size: .68rem;
  font-variant-numeric: tabular-nums;
  transition: color .15s ease;
}

.lesson-comments__count.is-near-limit { color: #e09a48; }

.lesson-comments__composer .lesson-comments__form-row button[type="submit"] {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  min-height: 41px;
  padding: .58rem 1rem;
  border: 1px solid color-mix(in srgb, var(--community-accent) 65%, transparent);
  border-radius: 11px;
  background: linear-gradient(135deg, var(--community-accent), color-mix(in srgb, var(--community-accent) 72%, #8d7aff));
  color: #fff;
  font: inherit;
  font-size: .78rem;
  font-weight: 800;
  box-shadow: 0 6px 16px color-mix(in srgb, var(--community-accent) 23%, transparent);
  cursor: pointer;
  transition: transform .15s ease, box-shadow .15s ease, opacity .15s ease;
}

.lesson-comments__composer .lesson-comments__form-row button[type="submit"] svg { width: 16px; height: 16px; stroke: currentColor; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }
.lesson-comments__composer .lesson-comments__form-row button[type="submit"]:hover:not(:disabled) {  box-shadow: 0 9px 20px color-mix(in srgb, var(--community-accent) 30%, transparent); }
.lesson-comments__form-row button:disabled { cursor: wait; opacity: .6; }

.lesson-comments__form--reply {
  margin-top: .65rem;
  padding: .8rem;
  border: 1px solid color-mix(in srgb, var(--community-accent) 19%, var(--color-border));
  border-inline-start: 3px solid var(--community-accent);
  border-radius: 12px;
  background: color-mix(in srgb, var(--community-accent) 5%, var(--color-surface));
}

.lesson-comments__form--reply textarea,
.lesson-comment__edit-form textarea { min-height: 76px; }
.lesson-comments__input-wrapper { width: 100%; min-width: 0; min-height: 44px; flex: 0 0 auto; align-self: stretch; }
.lesson-comments__composer .lesson-comments__input-wrapper { display: block; }
.lesson-comments__form .rich-input-highlighter__textarea { margin-top: 0; }
.lesson-comments__composer .rich-input-highlighter__mirror,
.lesson-comments__form--reply .rich-input-highlighter__mirror,
.lesson-comment__edit-form .rich-input-highlighter__mirror { overflow-wrap: anywhere; }
/* The composer auto-resizes and can scroll internally. Keep the textarea and
   its syntax mirror on identical Arabic font metrics and wrapping rules so
   native selection/caret geometry tracks highlighted glyphs after resize. */
.lesson-comments__composer .rich-input-highlighter__textarea,
.lesson-comments__composer .rich-input-highlighter__mirror {
  font-family: inherit !important;
  font-size: .84rem !important;
  line-height: 1.7 !important;
  letter-spacing: normal !important;
  white-space: pre-wrap !important;
  overflow-wrap: anywhere !important;
  word-break: normal !important;
}
.lesson-comment__body.md-content { overflow-wrap: anywhere; line-height: 1.75; }
.lesson-comment__body.md-content > :first-child { margin-top: 0; }
.lesson-comment__body.md-content > :last-child { margin-bottom: 0; }
.lesson-comment__body.md-content pre { max-width: 100%; overflow: auto; border-radius: 10px; }
.lesson-comment__body.md-content table { display: block; max-width: 100%; overflow-x: auto; }
.lesson-toc .doc-toc-link--comments { display: flex; align-items: center; gap: .45rem; color: var(--community-accent, var(--color-primary)); font-weight: 750; }
.lesson-toc .doc-toc-link--comments svg { width: 16px; height: 16px; flex: 0 0 auto; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.lesson-comments__form--reply .lesson-comments__form-row button,
.lesson-comment__edit-form button { min-height: 36px; padding: .45rem .8rem; border-radius: 9px; font-size: .74rem; }

.lesson-comments__error {
  padding: 1rem;
  border: 1px solid color-mix(in srgb, #e06c73 30%, var(--color-border));
  border-radius: 13px;
  background: color-mix(in srgb, #e06c73 7%, var(--color-surface));
  color: #e06c73;
  font-size: .8rem;
}

@media (max-width: 640px) {
  .lesson-comments { padding: 1rem; border-radius: 20px; }
  .lesson-comments__head { align-items: flex-start; }
  .lesson-comments__identity { gap: .7rem; }
  .lesson-comments__mark { width: 44px; height: 44px; border-radius: 14px; }
  .lesson-comments__mark svg { width: 21px; height: 21px; }
  .lesson-comments__heading-copy p { font-size: .75rem; }
  .lesson-comments__stat { min-width: 65px; padding: .55rem .5rem; }
  .lesson-comments__stat span { max-width: 58px; font-size: .56rem; text-align: center; white-space: normal; }
  .lesson-comments__toolbar { align-items: flex-start; flex-direction: column; }
  .lesson-comments__sort { width: 100%; justify-content: space-between; }
  .lesson-comments__sort-btn { flex: 1 1 auto; padding-inline: .45rem; font-size: .69rem; }
  .lesson-comment { padding: .85rem .8rem .7rem; }
  .lesson-comment__body { padding-inline-start: 0; font-size: .86rem; }
  .lesson-comment__meta { gap: .5rem; }
  .lesson-comment__avatar { width: 34px; height: 34px; flex-basis: 34px; border-radius: 11px; }
  .lesson-comment__meta time { font-size: .63rem; }
  .lesson-comment__edited { display: none; }
  .lesson-comment__actions { gap: .15rem; }
  .lesson-comment__react, .lesson-comment__link { padding-inline: .48rem; font-size: .68rem; }
  .lesson-comments__composer { padding: .8rem; }
  .lesson-comments__composer textarea { min-height: 44px; max-height: 180px; }
  .lesson-comment__author-card { width: min(320px, calc(100vw - 24px)); }
  .lesson-comment__actions { flex-wrap: wrap; }
  .lesson-comment__vote-group { max-width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  .lesson-comments *, .lesson-comments *::before, .lesson-comments *::after {
    animation-duration: .01ms !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ── Section Reveal & Adaptive Section Animations ── */
@keyframes lessonSectionReveal {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.lesson-section.animate-reveal {
  animation: lessonSectionReveal 0.45s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.lesson-section[hidden] {
  display: none !important;
}

/* ── Interactive Option Micro-animations ── */
.lesson-question__option {
  transition: transform 0.16s ease, border-color 0.2s ease, background-color 0.2s ease, box-shadow 0.2s ease;
}

.lesson-question__option:not([disabled]):hover {
  
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.lesson-question__option:not([disabled]):active {
  transform: translateY(0);
}

/* ── Feedback Reveal Animation ── */
.lesson-question__feedback {
  animation: lessonSectionReveal 0.35s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

/* ── Quiz-grade embedded questions (plan step 2) ─────────────────────────────
   Mirrors quiz.css option rows / feedback / formal-answer. State is carried by
   classes + data attributes set in lesson-blocks.js; nothing re-renders. */
.lesson-view .lesson-question__option {
  border-width: 2px;
  border-radius: 12px;
  padding: .9rem 1.1rem;
}

.lesson-view .lesson-question__option:not(:disabled):hover {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
  box-shadow: 0 4px 14px rgba(99, 102, 241, .12);
}

.lesson-view .lesson-question__option.is-selected:not(.is-correct):not(.is-wrong) {
  box-shadow: 0 0 0 4px rgba(99, 102, 241, .12);
}

.lesson-view .lesson-question__option:disabled {
  opacity: .92;
  cursor: default;
}

.lesson-view .lesson-question__option.is-correct {
  background: var(--color-success-light);
  border-color: var(--color-success);
  box-shadow: 0 0 0 4px rgba(16, 185, 129, .12);
}

.lesson-view .lesson-question__option.is-correct .lesson-question__option-marker {
  background: var(--color-success);
  border-color: var(--color-success);
}

.lesson-view .lesson-question__option.is-wrong {
  background: var(--color-error-light);
  border-color: var(--color-error);
  box-shadow: 0 0 0 4px rgba(239, 68, 68, .12);
}

.lesson-view .lesson-question__option.is-wrong .lesson-question__option-marker {
  background: var(--color-error);
  border-color: var(--color-error);
  color: #fff;
}

/* Correct option the reader missed in a multi-select question. */
.lesson-view .lesson-question__option.is-missed {
  border-style: dashed;
  border-color: var(--color-success);
  background: transparent;
}

.lesson-view .lesson-question__option.is-missed .lesson-question__option-marker {
  border-color: var(--color-success);
  color: var(--color-success);
}

[data-theme="dark"] .lesson-view .lesson-question__option.is-correct,
[data-theme="dark-slate"] .lesson-view .lesson-question__option.is-correct {
  background: rgba(16, 185, 129, .16);
}

[data-theme="dark"] .lesson-view .lesson-question__option.is-wrong,
[data-theme="dark-slate"] .lesson-view .lesson-question__option.is-wrong {
  background: rgba(239, 68, 68, .16);
}

/* Feedback card: verdict banner coloured by the question's result. */
.lesson-view .lesson-question__feedback {
  padding: 0;
  overflow: hidden;
  gap: 0;
  animation: lessonFeedbackFade .25s ease both;
}

.lesson-view .lesson-question__feedback > :not(.lesson-question__verdict) {
  margin: 0;
  padding: .85rem 1.1rem;
}

.lesson-view .lesson-question__feedback > .lesson-question__verdict + * {
  padding-top: 1rem;
}

.lesson-question__verdict {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .75rem 1.1rem;
  background: var(--color-background-secondary, var(--color-surface));
  font-weight: 800;
}

.lesson-question__verdict.is-correct {
  background: var(--color-success-light);
  color: #065f46;
}

.lesson-question__verdict.is-wrong {
  background: var(--color-error-light);
  color: #991b1b;
}

[data-theme="dark"] .lesson-question__verdict.is-correct,
[data-theme="dark-slate"] .lesson-question__verdict.is-correct {
  background: rgba(16, 185, 129, .18);
  color: #6ee7b7;
}

[data-theme="dark"] .lesson-question__verdict.is-wrong,
[data-theme="dark-slate"] .lesson-question__verdict.is-wrong {
  background: rgba(239, 68, 68, .18);
  color: #fca5a5;
}

.lesson-question__verdict-icon {
  display: grid;
  place-items: center;
  flex: 0 0 1.5rem;
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 50%;
  background: currentColor;
  font-size: .8rem;
  line-height: 1;
}

.lesson-question__verdict.is-correct .lesson-question__verdict-icon { background: var(--color-success); color: #fff; }
.lesson-question__verdict.is-wrong .lesson-question__verdict-icon { background: var(--color-error); color: #fff; }

.lesson-question__answer-label,
.lesson-question__explanation-label {
  display: block;
  margin-bottom: .3rem;
  color: var(--color-text-secondary);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .02em;
}

.lesson-view .lesson-question__explanation {
  border-top: 1px solid var(--color-border);
}

/* Essay: locked textarea, score badge, model answer in formal-answer style. */
.lesson-question[data-answered="true"] .lesson-question__essay-input {
  cursor: not-allowed;
  opacity: .8;
}

.lesson-question__essay-rating {
  display: flex;
  align-items: center;
  gap: .6rem;
}

.lesson-question__score-badge {
  padding: .15rem .65rem;
  border-radius: 999px;
  background: var(--color-primary);
  color: #fff;
  font-size: .85rem;
  font-weight: 800;
  letter-spacing: 0;
}

.lesson-question__stars {
  color: #f59e0b;
  letter-spacing: .1em;
}

.lesson-view .lesson-question__model-answer {
  margin: .25rem 1.1rem 1rem;
  padding: 1rem 1.2rem;
  border: 0;
  border-inline-start: 5px solid #0ea5e9;
  border-radius: 12px;
  background: linear-gradient(135deg, #e0f2fe 0%, #dbeafe 100%);
  color: #0c4a6e;
}

[data-theme="dark"] .lesson-view .lesson-question__model-answer,
[data-theme="dark-slate"] .lesson-view .lesson-question__model-answer {
  background: linear-gradient(135deg, rgba(14, 165, 233, .2) 0%, rgba(14, 165, 233, .1) 100%);
  color: var(--color-text-primary);
}

@keyframes lessonFeedbackFade {
  from { opacity: 0; }
  to { opacity: 1; }
}

html[data-motion="reduced"] .lesson-view .lesson-question__feedback {
  animation: none;
}

/* ── Heading anchor (copy deep link) — plan step 3 ── */
.lesson-anchor-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  width: 2rem;
  height: 2rem;
  padding: .35rem;
  border: 1px solid transparent;
  border-radius: .65rem;
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  opacity: 0;
  transition: opacity .15s ease, background-color .15s ease;
}

.lesson-anchor-btn .lesson-icon {
  display: block;
  width: 1rem;
  height: 1rem;
}

.lesson-section__header:hover .lesson-anchor-btn,
.lesson-anchor-btn:focus-visible,
.lesson-anchor-btn.is-copied {
  opacity: 1;
}

.lesson-anchor-btn:hover { background: var(--color-background-secondary, rgba(0, 0, 0, .05)); }
.lesson-anchor-btn.is-copied { color: var(--color-success); }

@media (hover: none) {
  .lesson-anchor-btn { opacity: .7; }
}

/* ── Reference card thumbnails (plan step 4) ─────────────────────────────── */
.lesson-ref-card__thumb {
  position: relative;
  grid-column: 1 / -1;
  aspect-ratio: 16 / 9;
  border-radius: 12px;
  overflow: hidden;
  background: linear-gradient(135deg, var(--color-primary-light), color-mix(in srgb, var(--color-primary) 22%, var(--color-surface)));
}

.lesson-ref-card--lesson .lesson-ref-card__thumb {
  background: linear-gradient(135deg, color-mix(in srgb, var(--color-success) 16%, var(--color-surface)), color-mix(in srgb, var(--color-success) 32%, var(--color-surface)));
}

.lesson-ref-card__thumb-fallback {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: .6rem;
  color: var(--color-primary);
}

.lesson-ref-card--lesson .lesson-ref-card__thumb-fallback { color: var(--color-success); }

.lesson-ref-card__thumb-fallback .lesson-icon { width: 2.2rem; height: 2.2rem; opacity: .75; }

.lesson-ref-card__thumb-img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

@media (min-width: 640px) {
  .lesson-ref-card--has-thumb {
    grid-template-columns: 180px minmax(0, 1fr);
    align-items: start;
  }

  .lesson-ref-card--has-thumb .lesson-ref-card__thumb {
    grid-column: 1;
    grid-row: 1 / span 2;
    align-self: stretch;
    aspect-ratio: auto;
    min-height: 101px;
  }

  .lesson-ref-card--has-thumb .lesson-ref-card__main,
  .lesson-ref-card--has-thumb .lesson-ref-card__actions {
    grid-column: 2;
  }

  .lesson-ref-card--has-thumb .lesson-ref-card__actions {
    justify-content: flex-start;
  }
}

@media (min-width: 640px) and (max-width: 760px) {
  .lesson-ref-card--has-thumb .lesson-ref-card__actions { width: auto; }
}

/* Link-out embeds (notebook / folder / course): anchors styled like the action buttons. */
a.lesson-ref-card__action {
  text-decoration: none;
}

.lesson-ref-card__action[aria-disabled="true"] {
  opacity: .5;
  cursor: not-allowed;
  pointer-events: none;
}

/* ── Recap card (plan step 8) ── */
.lesson-recap {
  margin-top: 2rem;
  padding: 1.25rem 1.4rem;
  border: 1px solid var(--color-border);
  border-radius: 16px;
  background: var(--color-surface);
}

.lesson-recap[hidden] { display: none; }

.lesson-recap__title { margin: 0 0 .75rem; font-size: 1.1rem; font-weight: 800; }

.lesson-recap__stats { display: flex; flex-wrap: wrap; gap: .5rem 1.25rem; font-weight: 700; }
.lesson-recap__stat--correct { color: var(--color-success); }

.lesson-recap__bar {
  height: 8px;
  margin: .75rem 0;
  border-radius: 999px;
  background: var(--color-border);
  overflow: hidden;
}

.lesson-recap__bar > span {
  display: block;
  height: 100%;
  width: 0;
  background: var(--color-primary);
  transition: width .25s ease;
}

.lesson-recap__wrong-title { margin: .75rem 0 .35rem; font-size: .85rem; font-weight: 800; color: var(--color-text-secondary); }
.lesson-recap__wrong { margin: 0 0 .75rem; padding-inline-start: 1.1rem; }
.lesson-recap__wrong a { color: var(--color-error); text-decoration: none; }
.lesson-recap__wrong a:hover { text-decoration: underline; }

.lesson-recap__retry {
  padding: .55rem 1rem;
  border: 2px solid var(--color-primary);
  border-radius: 10px;
  background: transparent;
  color: var(--color-primary);
  font: inherit;
  font-weight: 800;
  cursor: pointer;
}

.lesson-recap__retry:hover { background: var(--color-primary-light); }
html[data-motion="reduced"] .lesson-recap__bar > span { transition: none; }