/**
 * Lesson Page Styles
 * Premium lesson experience — white canvas, step dots, glass nav, transitions
 * All styles scoped to .lesson-page to avoid affecting other pages
 */

/* ═══════════════════════════════════════
   PHASE 1: WHITE CANVAS
   ═══════════════════════════════════════ */

/* Override Archivo Black headings within lesson scope — use Inter instead */
.lesson-page h1,
.lesson-page h2,
.lesson-page h3,
.lesson-page h4,
.lesson-page h5,
.lesson-page h6 {
  font-family: var(--font-family);
  text-transform: none;
}

html:has(.lesson-page) {
  background-color: var(--color-bg-page);
}

html:has(.lesson-page) body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
}

html:has(.lesson-page) main {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding: 0;
}

.lesson-page {
  --lesson-content-max-width: 720px;
  --lesson-section-gap: 32px;
  --lesson-block-gap: 16px;
  --lesson-heading-gap: 24px;

  display: flex;
  flex-direction: column;
  flex: 1;
  width: 100%;
  gap: var(--spacing-lg);
  padding: 0 var(--spacing-md);
  max-width: 900px;
  margin: 0 auto;
  /* Bottom spacing for fixed nav bar + PWA banner */
  padding-bottom: 120px;
  overflow-x: hidden;
  box-sizing: border-box;
}

/* Make island wrappers transparent to layout so sticky works inside scroll container */
.lesson-page > honox-island,
.lesson-page > honox-island > [data-testid="lesson-screen-navigator"] {
  display: contents;
}

/* Ensure nav renders below content on mobile (DOM order has nav before content) */
#screen-content-container {
  order: 1;
  position: relative;
  z-index: 0;
  overflow: hidden;
  isolation: isolate;
}

.screen-nav-premium {
  order: 2;
}

/* ═══════════════════════════════════════
   PHASE 2: LESSON PROGRESS HEADER
   ═══════════════════════════════════════ */

.lesson-progress-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: 14px 0;
  border-bottom: 1px solid var(--color-border-light);
  position: sticky;
  top: 0;
  z-index: calc(var(--z-sticky) - 1);
  background: rgba(var(--color-background-rgb, 255,255,255), 0.98);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

/* Center section: title + dots */
.lesson-progress-center {
  flex: 1;
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-width: 0;
}

.lesson-progress-title {
  font-family: var(--font-family);
  font-size: var(--font-size-2xs);
  font-weight: var(--font-weight-bold);
  color: var(--color-course-text-muted);
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 100%;
  text-align: left;
}

@media (max-width: 480px) {
  .lesson-progress-center {
    flex-direction: column;
    gap: 8px;
  }
}

/* Step dots container */
.lesson-progress-dots {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: center;
}

/* Individual step dot */
.lesson-progress-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: none;
  background-color: var(--color-border-light);
  transition: background-color 400ms cubic-bezier(0.16, 1, 0.3, 1),
              box-shadow 400ms cubic-bezier(0.16, 1, 0.3, 1);
  flex-shrink: 0;
}

/* Completed dot */
.lesson-progress-dot--completed {
  background-color: var(--color-progress);
}

/* Current dot — ring shadow, no pulse */
.lesson-progress-dot--current {
  background-color: var(--color-progress);
  box-shadow: 0 0 0 2px var(--color-surface), 0 0 0 3px var(--color-progress);
}

/* ═══════════════════════════════════════
   PHASE 3: CONTENT TYPOGRAPHY
   ═══════════════════════════════════════ */

/* Content screen container */
.lesson-content-screen {
  display: flex;
  flex-direction: column;
  gap: var(--lesson-block-gap);
  padding: 40px;
  max-width: var(--lesson-content-max-width);
  margin: 0 auto;
  width: 100%;
  box-sizing: border-box;
  overflow-x: hidden;
  background-color: var(--color-bg-page);
  border-radius: var(--radius-lg);
}

/* Section label — small, understated */
.lesson-section-label {
  font-family: var(--font-family);
  font-size: var(--font-size-sm-plus);
  font-weight: var(--font-weight-semibold);
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  text-transform: uppercase;
  margin: 0;
}

/* Main heading — Inter, normal case (override Archivo Black in lesson scope) */
.lesson-content-screen h2 {
  font-family: var(--font-family);
  font-size: var(--font-size-2xl-plus);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-heading);
  text-transform: none;
  letter-spacing: normal;
  line-height: var(--line-height-snug);
}

/* Subheading */
.lesson-content-screen h3 {
  font-family: var(--font-family);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-heading);
  text-transform: none;
  letter-spacing: normal;
  line-height: var(--line-height-snug);
}

/* Headings inside content — breathing room below, section separation above */
.lesson-content-screen [data-testid="screen-content"] h2,
[data-testid="summary-content"] h2 {
  margin-top: var(--lesson-section-gap);
  margin-bottom: var(--lesson-heading-gap);
}

.lesson-content-screen [data-testid="screen-content"] h3,
[data-testid="summary-content"] h3 {
  margin-top: var(--lesson-section-gap);
  margin-bottom: var(--lesson-block-gap, 16px);
}

.lesson-content-screen [data-testid="screen-content"] h4,
[data-testid="summary-content"] h4 {
  font-family: var(--font-family);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  text-transform: none;
  letter-spacing: normal;
  line-height: var(--line-height-snug);
}

/* First heading in content — no top margin */
.lesson-content-screen [data-testid="screen-content"] > h2:first-child,
.lesson-content-screen [data-testid="screen-content"] > h3:first-child,
.lesson-content-screen [data-testid="screen-content"] > h4:first-child,
[data-testid="summary-content"] > h2:first-child,
[data-testid="summary-content"] > h3:first-child,
[data-testid="summary-content"] > h4:first-child {
  margin-top: 0;
}

/* Body text */
.lesson-content-screen [data-testid="screen-content"],
[data-testid="summary-content"] {
  font-family: var(--font-family);
  font-size: var(--font-size-base-minus);
  line-height: 1.6;
  color: var(--color-text-body);
  max-width: 70ch;
}

/* Lead text (first paragraph) */
.lesson-content-screen [data-testid="screen-content"] > p:first-child {
  font-size: var(--font-size-xl);
  line-height: 1.4;
  color: var(--color-text);
}

/* Paragraph spacing */
/* Key terms — accent color on bold text for visual anchoring */
.lesson-content-screen [data-testid="screen-content"] strong {
  color: var(--color-accent);
  font-weight: 700;
}

.lesson-content-screen [data-testid="screen-content"] p,
[data-testid="summary-content"] p {
  margin-bottom: var(--lesson-block-gap);
}

.lesson-content-screen [data-testid="screen-content"] p:last-child,
[data-testid="summary-content"] p:last-child {
  margin-bottom: 0;
}

/* MDX custom component spacing — matches content rhythm */
.lesson-content-screen [data-testid="screen-content"] .mdx-component,
[data-testid="summary-content"] .mdx-component {
  margin: var(--lesson-section-gap) 0 var(--lesson-block-gap) 0;
}

/* Tables in lesson content — breathing room above and below */
.lesson-content-screen [data-testid="screen-content"] .table-wrapper,
[data-testid="summary-content"] .table-wrapper {
  margin-top: var(--lesson-section-gap);
  margin-bottom: var(--lesson-block-gap);
}
.lesson-content-screen [data-testid="screen-content"] > .mdx-component:first-child,
[data-testid="summary-content"] > .mdx-component:first-child {
  margin-top: 0;
}
.lesson-content-screen [data-testid="screen-content"] > .mdx-component:last-child,
[data-testid="summary-content"] > .mdx-component:last-child {
  margin-bottom: 0;
}

/* ═══ Arrow bullets ═══ */
.lesson-page .screen-content ul {
  list-style: none;
  padding-left: 28px;
}

.lesson-page .screen-content ul li {
  position: relative;
  margin-bottom: 12px;
  line-height: 1.6;
}

.lesson-page .screen-content ul li::before {
  content: '\2192';
  position: absolute;
  left: -28px;
  color: var(--color-main);
  opacity: 0.65;
  font-weight: var(--font-weight-medium);
}

/* List spacing — match content rhythm */
.lesson-content-screen [data-testid="screen-content"] ul,
.lesson-content-screen [data-testid="screen-content"] ol,
[data-testid="summary-content"] ul,
[data-testid="summary-content"] ol {
  margin-bottom: var(--lesson-block-gap);
}
.lesson-content-screen [data-testid="screen-content"] ul:last-child,
.lesson-content-screen [data-testid="screen-content"] ol:last-child,
[data-testid="summary-content"] ul:last-child,
[data-testid="summary-content"] ol:last-child {
  margin-bottom: 0;
}

/* ═══ Callout boxes (blockquotes) ═══ */
.lesson-page .screen-content blockquote {
  background: none;
  border: none;
  border-left: 4px solid var(--color-course-border);
  border-radius: 0;
  padding: 20px;
  margin: var(--lesson-block-gap) 0;
  font-style: italic;
  color: var(--color-text);
}

.lesson-page .screen-content blockquote p {
  margin-bottom: var(--spacing-sm);
}

.lesson-page .screen-content blockquote p:last-child {
  margin-bottom: 0;
}

/* Strong text in callouts */
.lesson-page .screen-content blockquote strong {
  color: var(--color-main);
}

/* Callout variants */
.lesson-page .screen-content blockquote.callout--info,
.lesson-page .screen-content [data-variant="info"] {
  border-left-color: var(--color-info);
  background: var(--color-info-bg);
}

.lesson-page .screen-content blockquote.callout--warning,
.lesson-page .screen-content [data-variant="warning"] {
  border-left-color: var(--color-warning);
  background: var(--color-warning-bg);
}

.lesson-page .screen-content blockquote.callout--tip,
.lesson-page .screen-content [data-variant="tip"] {
  border-left-color: var(--color-success);
  background: var(--color-success-bg);
}

/* ═══════════════════════════════════════
   PHASE 4: SCREEN TRANSITIONS
   ═══════════════════════════════════════ */

/* Screen entrance animation */
@keyframes screen-enter {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Screen exit animation */
@keyframes screen-exit {
  from {
    opacity: 1;
    transform: translateY(0);
  }
  to {
    opacity: 0;
    transform: translateY(-8px);
  }
}

.screen-content {
  will-change: auto;
}

/* Active screen gets view-transition-name for View Transitions API */
.screen-content[style*="display: block"] {
  view-transition-name: slide-content;
}

/* ═══════════════════════════════════════
   VIEW TRANSITIONS API — Slide Animations
   ═══════════════════════════════════════ */

::view-transition-old(slide-content) {
  animation: slide-out-left 150ms cubic-bezier(0.25, 0.1, 0.25, 1.0) forwards;
}

::view-transition-new(slide-content) {
  animation: slide-in-right 180ms cubic-bezier(0.25, 0.1, 0.25, 1.0) forwards;
}

/* Forward direction */
[data-slide-direction="forward"]::view-transition-old(slide-content) {
  animation-name: slide-out-left;
}
[data-slide-direction="forward"]::view-transition-new(slide-content) {
  animation-name: slide-in-right;
}

/* Backward direction */
[data-slide-direction="backward"]::view-transition-old(slide-content) {
  animation-name: slide-out-right;
}
[data-slide-direction="backward"]::view-transition-new(slide-content) {
  animation-name: slide-in-left;
}

@keyframes slide-out-left {
  to { opacity: 0; transform: translateX(-8%); }
}
@keyframes slide-in-right {
  from { opacity: 0; transform: translateX(15%); }
}
@keyframes slide-out-right {
  to { opacity: 0; transform: translateX(8%); }
}
@keyframes slide-in-left {
  from { opacity: 0; transform: translateX(-15%); }
}

/* Keep nav bar static (no animation) during view transitions */
::view-transition-old(screen-nav),
::view-transition-new(screen-nav) {
  animation: none;
}

/* Respect reduced motion for View Transitions */
@media (prefers-reduced-motion: reduce) {
  ::view-transition-old(slide-content),
  ::view-transition-new(slide-content) {
    animation: none !important;
  }
}

/* Uniform width constraint for ALL screen types (content, summary, video, quiz) */
.lesson-page .screen-content {
  max-width: var(--lesson-content-max-width);
  margin-left: auto;
  margin-right: auto;
  width: 100%;
  box-sizing: border-box;
}

.screen-entering {
  animation: screen-enter 300ms ease-out forwards;
  will-change: transform, opacity;
}

.screen-exiting {
  animation: screen-exit 200ms ease-in forwards;
  will-change: transform, opacity;
  pointer-events: none;
}

/* Content element stagger */
.screen-entering > * {
  opacity: 0;
  animation: screen-enter 300ms ease-out forwards;
}

.screen-entering > *:nth-child(1) { animation-delay: 0ms; }
.screen-entering > *:nth-child(2) { animation-delay: 50ms; }
.screen-entering > *:nth-child(3) { animation-delay: 100ms; }
.screen-entering > *:nth-child(4) { animation-delay: 150ms; }
.screen-entering > *:nth-child(5) { animation-delay: 200ms; }
.screen-entering > *:nth-child(6) { animation-delay: 250ms; }

/* ═══════════════════════════════════════
   PHASE 5: PREMIUM NAVIGATION BAR
   ═══════════════════════════════════════ */

.screen-nav-premium {
  position: sticky;
  bottom: 0;
  display: flex;
  flex-wrap: nowrap;
  justify-content: space-between;
  align-items: center;
  padding: 4px 16px;
  background: var(--color-surface);
  border-top: 1px solid var(--color-course-border, var(--color-border));
  z-index: var(--z-sticky);
  gap: 0;
  /* Keep nav in its own View Transition layer so slide animations don't cover it */
  view-transition-name: screen-nav;
}

/* Previous button — ghost style */
.screen-nav-prev {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: 6px 24px;
  font-family: var(--font-family);
  font-size: var(--font-size-sm);
  font-weight: 600;
  line-height: 1;
  color: var(--color-course-text-muted);
  background-color: transparent;
  border: 1.5px solid var(--color-course-border);
  border-radius: 24px;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.screen-nav-prev:hover {
  border-color: var(--color-text-muted);
  color: var(--color-text);
  background-color: var(--color-surface-hover);
  transform: translateY(-1px);
  text-decoration: none;
}

.screen-nav-prev:active {
  transform: translateY(0);
}

.screen-nav-prev:focus-visible {
  outline: 2px solid var(--color-main);
  outline-offset: 2px;
}

/* Next button — premium filled */
.screen-nav-next {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: 6px 24px;
  font-family: var(--font-family);
  font-size: var(--font-size-sm);
  font-weight: 600;
  line-height: 1;
  color: var(--color-text-inverse);
  background-color: var(--color-btn-primary);
  border: none;
  border-radius: 24px;
  text-decoration: none;
  cursor: pointer;
  text-align: center;
  transition: all 150ms ease-out;
}

.screen-nav-next:hover {
  background-color: var(--color-btn-primary-hover);
  text-decoration: none;
  color: var(--color-text-inverse);
}

.screen-nav-next:active {
  transform: translateY(0);
  box-shadow: 0 2px 8px rgba(75, 96, 110, 0.2);
}

.screen-nav-next:focus-visible {
  outline: 2px solid var(--color-main);
  outline-offset: 2px;
}

/* Disabled next button */
.screen-nav-next--disabled {
  background-color: var(--color-border-light);
  color: var(--color-text-inverse);
  box-shadow: none;
  cursor: not-allowed;
  opacity: 0.7;
}

.screen-nav-next--disabled:hover {
  transform: none;
  box-shadow: none;
}

/* Placeholder for empty button space */
.screen-nav-placeholder {
  min-width: 48px;
  min-height: 48px;
}

/* ═══════════════════════════════════════
   PHASE 5b: DESKTOP INLINE NAVIGATION
   Nav bar becomes static (under content) on desktop
   ═══════════════════════════════════════ */

/* Column wrappers */
.screen-nav-col {
  flex: 1;
  display: flex;
  align-items: center;
}

.screen-nav-col--prev {
  justify-content: flex-start;
}

.screen-nav-col--next {
  justify-content: flex-end;
}

/* Keyboard navigation hint — desktop only */
.screen-nav-col--center {
  flex: 1;
  display: none;
  justify-content: center;
  align-items: center;
}

.screen-nav-keyboard-hint {
  font-size: var(--font-size-2xs);
  line-height: 1;
  color: var(--color-text-muted);
  opacity: 0.5;
  margin: 0;
  padding: 0;
  pointer-events: none;
  white-space: nowrap;
}

@media (min-width: 768px) {
  .screen-nav-col--center {
    display: flex;
  }
}

/* Desktop: nav bar moves below content instead of fixed bottom */
@media (min-width: 1024px) {
  /* Island wrappers become transparent so their children join .lesson-page flex.
     HonoX wraps islands in <honox-island>, so we need contents on both layers. */
  [data-testid="lesson-screen-navigator"],
  [data-testid="lesson-screen-navigator"]:where(honox-island > *) {
    display: contents;
  }

  .lesson-page > honox-island:has([data-testid="lesson-screen-navigator"]) {
    display: contents;
  }

  /* Progress header stays at top */
  .lesson-progress-header {
    order: 0;
  }

  /* Content in the middle — flex:1 pushes nav to bottom of lesson-page */
  #screen-content-container {
    order: 1;
    flex: 1;
    position: relative;
    z-index: 0;
  }

  /* Nav bar sticky full-width at bottom */
  .screen-nav-premium {
    order: 2;
    width: 100%;
    padding: 4px 40px;
  }

  /* Keep symmetric padding so text stays centered within buttons */

  /* Remove extra bottom padding — no fixed bottom bar on desktop */
  .lesson-page {
    padding-bottom: 0;
    gap: 0;
  }

  /* Reduce progress header vertical padding on desktop */
  .lesson-progress-header {
    padding: var(--spacing-xs) 0;
  }

  /* Improved content padding on desktop */
  .lesson-content-screen {
    padding: 48px 56px;
  }
}

/* ═══════════════════════════════════════
   PHASE 6: COMPACT FEEDBACK WIDGET
   ═══════════════════════════════════════ */

.feedback-compact-trigger {
  position: fixed;
  bottom: var(--spacing-md);
  right: var(--spacing-md);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 999;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-fast);
  color: var(--color-main);
  font-family: var(--font-family);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  line-height: 1;
  padding: 0;
}

.feedback-compact-trigger:hover {
  background-color: var(--color-surface-hover);
  border-color: var(--color-border);
  color: var(--color-text);
  box-shadow: var(--shadow-md);
}

/* Compact popover */
.feedback-compact-popover {
  position: fixed;
  bottom: 60px;
  right: var(--spacing-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 999;
  padding: var(--spacing-xs) 0;
  min-width: 180px;
}

.feedback-compact-popover-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-family);
  font-size: var(--font-size-sm);
  color: var(--color-text);
  background: transparent;
  border: none;
  cursor: pointer;
  width: 100%;
  text-align: left;
  transition: background var(--transition-fast);
}

.feedback-compact-popover-item:hover {
  background-color: var(--color-surface-hover);
}

/* ═══════════════════════════════════════
   LESSON CARD LAYOUT (Desktop)
   One cohesive card with sidebar + content + footer inside
   Reference: research/prototypes/432-lesson-1-2-interview.html
   ═══════════════════════════════════════ */

/* Gray background behind the card */
html:has(.lesson-card-wrapper) {
  background: var(--color-course-border);
  overflow: hidden;
}

html:has(.lesson-card-wrapper) body {
  background: var(--color-course-border);
  overflow: hidden;
  height: 100vh;
}

/* The card itself */
.lesson-card {
  background: var(--color-bg-page);
  border-radius: 12px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.08);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  height: calc(100vh - var(--header-height, 73px));
  max-width: 1440px;
  margin: 0 auto;
}

/* Body: sidebar + main content side by side */
.lesson-body {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* Main content area (next to sidebar) */
.lesson-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* Override lesson-page to fill the main area */
html:has(.lesson-card) .lesson-page {
  max-width: none;
  padding: 0;
  padding-bottom: 0;
  margin: 0;
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* Content scrolls inside the card, not on body */
html:has(.lesson-card) #screen-content-container {
  flex: 1;
  overflow-y: auto;
  padding: 0 var(--spacing-md);
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
}

html:has(.lesson-card) #screen-content-container::-webkit-scrollbar {
  width: 6px;
}

html:has(.lesson-card) #screen-content-container::-webkit-scrollbar-track {
  background: transparent;
}

html:has(.lesson-card) #screen-content-container::-webkit-scrollbar-thumb {
  background: rgba(75, 96, 110, 0.15);
  border-radius: 3px;
}

html:has(.lesson-card) #screen-content-container::-webkit-scrollbar-thumb:hover {
  background: rgba(75, 96, 110, 0.25);
}

/* Nav bar at bottom of card (not sticky - flexbox keeps it at bottom) */
html:has(.lesson-card) .screen-nav-premium {
  position: static;
  flex-shrink: 0;
  width: 100%;
  max-width: none;
  margin: 0;
  padding: 4px 40px;
  background: var(--color-surface);
  border-top: 1px solid var(--color-course-border);
  box-shadow: none;
}

/* ═══════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════ */

@media (max-width: 1023px) {
  .lesson-content-screen {
    padding: 24px;
  }

  .lesson-content-screen h2 {
    font-size: 24px;
  }

  .lesson-content-screen h3 {
    font-size: 16px;
  }

  /* Card fills screen on mobile, no rounded corners */
  .lesson-card {
    border-radius: 0;
    box-shadow: none;
    height: auto;
    min-height: auto;
  }

  /* Body scrolls normally on mobile */
  html:has(.lesson-card-wrapper) {
    overflow: auto;
    background: var(--color-bg-page);
  }
  html:has(.lesson-card-wrapper) body {
    overflow: auto;
    height: auto;
  }

  /* Content doesn't need scroll container on mobile */
  html:has(.lesson-card) #screen-content-container {
    overflow-y: visible;
    padding: 0 var(--spacing-sm);
  }

  /* Lesson page gets normal padding back on mobile */
  html:has(.lesson-card) .lesson-page {
    padding-bottom: 120px;
  }

  /* Nav is sticky on mobile (bottom of viewport) */
  html:has(.lesson-card) .screen-nav-premium {
    position: sticky;
    bottom: 0;
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
  }
}

@media (max-width: 767px) {
  .lesson-content-screen {
    padding: 16px;
  }

  .lesson-content-screen h2 {
    font-size: 24px;
  }

  .lesson-content-screen h3 {
    font-size: 16px;
  }

  .lesson-content-screen [data-testid="screen-content"] > p:first-child {
    font-size: var(--font-size-lg);
  }

  .lesson-progress-header {
    gap: var(--spacing-sm);
  }

  .lesson-progress-title {
    font-size: var(--font-size-2xs);
  }

  .lesson-progress-dots {
    gap: 6px;
  }

  .screen-nav-premium {
    padding: 4px 12px;
  }

  .lesson-page {
    padding: 0 var(--spacing-sm);
    padding-bottom: var(--spacing-md);
  }

  /* Prevent horizontal scroll on small screens */
  .lesson-content-screen img,
  .lesson-content-screen video,
  .lesson-content-screen pre,
  .lesson-content-screen iframe {
    max-width: 100%;
    overflow-x: auto;
  }
}

/* ═══════════════════════════════════════
   REDUCED MOTION
   ═══════════════════════════════════════ */

@media (prefers-reduced-motion: reduce) {
  .lesson-progress-dot--current {
    box-shadow: 0 0 0 2px var(--color-surface), 0 0 0 3px var(--color-progress);
  }

  .screen-entering,
  .screen-exiting {
    animation: none;
  }

  .screen-entering > * {
    animation: none;
    opacity: 1;
  }

  .screen-nav-next:hover {
    transform: none;
  }

  .screen-nav-next:active {
    transform: none;
  }
}

/* ═══════════════════════════════════════
   LESSON INTRO SCREEN (Opener) — #432
   ═══════════════════════════════════════ */

.lesson-intro-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  min-height: 60vh;
  padding: var(--spacing-xl) var(--spacing-md);
  animation: intro-fade-in 600ms ease-out;
}

@keyframes intro-fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.lesson-intro-label {
  font-size: var(--font-size-2xs);
  text-transform: uppercase;
  letter-spacing: 1.2px;
  font-weight: 700;
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-lg);
  animation: intro-element-in 400ms ease-out both;
}

.lesson-intro-title {
  font-family: var(--font-family);
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-text);
  margin: 0 0 var(--spacing-sm);
  line-height: 1.2;
  max-width: 400px;
  animation: intro-element-in 400ms ease-out 150ms both;
}

.screen-hook {
  font-size: var(--font-size-lg);
  line-height: 1.5;
  margin-bottom: 1rem;
}

.lesson-intro-hook {
  font-size: var(--font-size-lg);
  color: var(--color-text-muted);
  line-height: 1.5;
  max-width: 320px;
  margin: 0;
  animation: intro-element-in 400ms ease-out 300ms both;
}

@keyframes intro-element-in {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* Module accent color overrides */
[data-module="fundamenty"] .lesson-intro-label   { color: var(--color-module-fundamenty); }
[data-module="temperatura"] .lesson-intro-label   { color: var(--color-module-temperatura); }
[data-module="toolkit"] .lesson-intro-label       { color: var(--color-module-toolkit); }
[data-module="zaawansowane"] .lesson-intro-label  { color: var(--color-module-zaawansowane); }

/* ═══════════════════════════════════════
   KEY CONCEPTS RESPONSIVE GRID
   ═══════════════════════════════════════ */

@media (min-width: 768px) {
  [data-testid="key-concepts"] > div:last-child {
    grid-template-columns: repeat(2, 1fr) !important;
  }
}

@media (min-width: 1200px) {
  [data-testid="key-concepts"] > div:last-child {
    grid-template-columns: repeat(3, 1fr) !important;
  }
}