:root {
  color-scheme: light;
  --font-display: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-body: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-reading: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-ui: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SFMono-Regular", Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  --bg: #f4f6f8;
  --bg-alt: #eef2f6;
  --surface: #ffffff;
  --surface-strong: #f8fafc;
  --panel: #ffffff;
  --panel-2: #f1f5f9;
  --line: #d7dee8;
  --text: #1f2937;
  --muted: #5f6b7a;
  --muted-strong: #334155;
  --cyan: #0f6cbf;
  --blue: #2878bd;
  --blue-deep: #0b4f82;
  --green: #217a4b;
  --amber: #a15c00;
  --white: #ffffff;
  --accent: var(--cyan);
  --accent-2: var(--blue-deep);
  --shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
  --radius: 8px;
  --narration-dock-height: 0px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
}

body.graphic-zoom-active {
  overflow: hidden;
}

body.narration-dock-active {
  padding-bottom: calc(var(--narration-dock-height) + 16px);
}

.wrap {
  max-width: none;
  margin: 0 auto;
  padding: 20px;
}

.main-content.course-layout {
  width: 100%;
  max-width: none;
  margin: 0;
  padding: 20px;
  display: grid;
  grid-template-columns: minmax(230px, 280px) minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}

.main-content.course-layout .wrap {
  max-width: none;
  margin: 0;
  padding: 0;
}

.course-nav-pane {
  position: sticky;
  top: 14px;
  align-self: start;
}

.course-nav-title {
  margin: 0 0 10px;
  color: var(--cyan);
  font-family: var(--font-ui);
  font-size: 0.86rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.course-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 5px;
}

.course-nav-link {
  display: block;
  border-radius: var(--radius);
  border: 1px solid transparent;
  padding: 8px 10px;
  color: var(--text);
  text-decoration: none;
  line-height: 1.35;
  font-size: 14px;
  transition: border-color 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.course-nav-link:hover {
  background: #edf3f8;
  border-color: #b8c7d6;
}

.course-nav-link.current {
  background: #e5f0fa;
  border-color: var(--cyan);
  color: #103a5c;
  font-weight: 700;
}

.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 14px;
  box-shadow: 0 2px 8px rgba(15, 23, 42, 0.05);
}

.title-card {
  text-align: center;
  padding: 0;
  margin-bottom: 10px;
  border: 0;
  background: transparent;
  box-shadow: none;
}

.title-card h1 {
  margin: 0;
}

.title-card-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.hidden {
  display: none !important;
}

.code-example-card-hidden {
  display: none !important;
}

.code-example-card-user-hidden {
  display: none !important;
}

.screen-text-card-hidden {
  display: none !important;
}

.screen-text-card {
  position: relative;
  overflow: hidden;
  padding: 18px 18px 18px 28px;
  border-color: #c9d7e5;
  background: linear-gradient(135deg, #ffffff, #f7f9fc);
  box-shadow: var(--shadow);
}

.screen-text-card::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 4px;
  background: var(--cyan);
}

.screen-text-card::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  left: 0;
  height: 1px;
  background: linear-gradient(90deg, #c8dff2, transparent 72%);
}

.screen-text-card h2 {
  margin: 0 0 12px;
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  line-height: 1.1;
  text-transform: uppercase;
}

.screen-text-list {
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
  list-style: none;
}

.screen-text-list li {
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr);
  align-items: flex-start;
  column-gap: 12px;
  margin: 0;
  color: var(--muted-strong);
  font-family: var(--font-reading);
  font-size: clamp(1rem, 1.4vw, 1.25rem);
  font-weight: 600;
  line-height: 1.22;
  overflow-wrap: break-word;
}

.screen-text-list li::before {
  content: "+";
  display: block;
  margin-top: 0.08em;
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 1.08em;
  font-weight: 400;
  line-height: 1;
  text-align: center;
}

.graphic-card-hidden {
  display: none !important;
}

.graphic-card {
  padding: 0;
  margin: 0 0 14px;
  border: 1px solid var(--line);
  background: var(--panel);
  box-shadow: var(--shadow);
  overflow: hidden;
  line-height: 0;
  transition: margin 160ms ease, padding 160ms ease, border-radius 160ms ease;
}

.module-graphic {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 0;
  cursor: zoom-in;
}

.module-graphic:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

.graphic-card.is-expanded,
.graphic-card:fullscreen,
.graphic-card:-webkit-full-screen {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  max-width: none;
  margin: 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: var(--bg);
  box-shadow: none;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000;
}

.graphic-card.is-expanded .module-graphic,
.graphic-card:fullscreen .module-graphic,
.graphic-card:-webkit-full-screen .module-graphic {
  width: 100%;
  height: 100%;
  max-width: 100vw;
  max-height: 100vh;
  object-fit: contain;
  border-radius: 0;
  cursor: zoom-out;
}

.badge {
  display: inline-block;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  background: #e8f2fb;
  border: 1px solid #b8d4ea;
  color: var(--cyan);
  padding: 4px 9px;
  border-radius: 999px;
  font-weight: 700;
  margin-bottom: 8px;
}

h1, h2 {
  margin: 0 0 8px;
  line-height: 1.2;
  letter-spacing: 0;
}

h1 {
  color: #17324d;
  font-family: var(--font-display);
  font-weight: 650;
  font-size: clamp(1.35rem, 2vw, 2rem);
  letter-spacing: -0.015em;
}

h2 {
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 1.15rem;
  font-weight: 700;
}

.meta, .status {
  color: var(--muted);
  margin: 0;
}

.meta {
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.status {
  color: var(--muted);
  font-size: 0.9rem;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 12px;
}

button, .btn {
  border: 1px solid var(--blue-deep);
  border-radius: 999px;
  padding: 9px 12px;
  cursor: pointer;
  font-family: var(--font-ui);
  font-weight: 700;
  color: var(--white);
  background: var(--cyan);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1.2;
  min-height: 38px;
  box-shadow: 0 2px 5px rgba(15, 23, 42, 0.12);
  transition: border-color 0.18s ease, background 0.18s ease, box-shadow 0.18s ease;
}

button:hover, .btn:hover {
  border-color: #073b62;
  background: var(--blue-deep);
  box-shadow: 0 3px 8px rgba(15, 23, 42, 0.16);
}

.btn.secondary {
  border-color: #aebac7;
  background: var(--white);
  color: #23415d;
}

.btn.secondary:hover {
  border-color: #7f91a3;
  background: #edf3f8;
}

ul { margin: 8px 0; }
li { margin: 5px 0; }
.progress { font-size: 13px; color: var(--muted); margin-top: 8px; }

.slide-status-footer {
  margin: 8px 0 0;
  padding: 8px 16px 2px;
  color: var(--muted);
  font-family: var(--font-ui);
  font-size: 0.82rem;
  line-height: 1.4;
  text-align: center;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 1000;
  border: 1px solid var(--cyan);
  background: var(--white);
  color: var(--text);
  font-weight: 700;
  padding: 10px 14px;
  border-radius: 0 0 var(--radius) var(--radius);
  text-decoration: none;
}

.skip-link:focus,
.skip-link:focus-visible {
  left: 12px;
  top: 0;
}

a { color: var(--cyan); }

a:not(.btn) {
  text-decoration: underline;
  text-underline-offset: 2px;
}

a.course-nav-link {
  text-decoration: none;
}

button:focus-visible,
.btn:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible,
audio:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 4px;
}

button:disabled,
.btn[aria-disabled="true"] {
  opacity: 0.65;
  cursor: not-allowed;
}

.narration-player-card {
  position: fixed;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 9000;
  max-height: min(48vh, 360px);
  margin: 0;
  padding: 10px 16px 12px;
  overflow-y: auto;
  border-color: #c9d7e5;
  border-right: 0;
  border-bottom: 0;
  border-left: 0;
  border-radius: 0;
  background: var(--surface);
  box-shadow: 0 -8px 24px rgba(15, 23, 42, 0.12);
}

.narration-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-start;
  gap: 8px;
  margin: 6px 0 0;
}

.narration-controls .narration-nav {
  margin-top: 0;
  justify-content: flex-start;
}

.narration-controls .btn,
.narration-controls button {
  min-height: 38px;
  height: 38px;
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1.2;
}

.narration-speed-label {
  font-size: 12px;
  color: var(--muted);
  margin-left: 4px;
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.narration-speed {
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--white);
  color: var(--text);
  padding: 7px 9px;
  min-height: 38px;
}

.narration-audio {
  width: 100%;
  margin-top: 2px;
  color-scheme: light;
}

.narration-cc {
  margin: 0 0 8px;
  padding: 10px 12px;
  border-radius: var(--radius);
  border: 1px solid #c9d7e5;
  background: #f8fafc;
  color: var(--muted-strong);
  font-family: var(--font-reading);
  line-height: 1.45;
}

.narration-cc.hidden {
  display: none;
}

.narration-card p {
  font-family: var(--font-reading);
  margin: 0 0 12px;
}

.narration-card p:last-child {
  margin-bottom: 0;
}

.code-example-card {
  display: grid;
  gap: 16px;
}

.code-example-intro,
.code-example-blurb {
  color: var(--muted-strong);
  font-family: var(--font-reading);
  margin: 0;
}

.code-example-list {
  display: grid;
  gap: 18px;
}

.code-example {
  display: grid;
  gap: 8px;
}

.code-example-title {
  margin: 0;
  color: var(--cyan);
  font-family: var(--font-ui);
  font-size: 1rem;
  letter-spacing: 0;
}

.code-figure {
  margin: 0;
}

.code-block {
  margin: 0;
  max-width: 100%;
  overflow: auto;
  border: 1px solid #b8c7d6;
  border-radius: var(--radius);
  background: #030914;
  color: #e8f4ff;
  padding: 16px;
  font-family: var(--font-mono);
  font-size: 0.95rem;
  line-height: 1.55;
  tab-size: 4;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.035);
}

.code-block code {
  font-family: inherit;
}

.code-block:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

.tok-keyword { color: #67e8f9; }
.tok-register { color: #facc15; }
.tok-number { color: #86efac; }
.tok-label { color: #f0abfc; }
.tok-string { color: #fdba74; }
.tok-parameter { color: #93c5fd; }
.tok-comment { color: #9ca3af; font-style: italic; }

#quiz-result:focus {
  outline: none;
}

.quiz-form {
  display: grid;
  gap: 10px;
}

.quiz-question {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  margin: 0;
  background: #f8fafc;
}

.quiz-question legend {
  color: var(--text);
  font-family: var(--font-ui);
  font-weight: 700;
  margin-bottom: 8px;
}

.quiz-question label {
  display: block;
  font-family: var(--font-reading);
  margin: 6px 0;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

@media (max-width: 980px) {
  .main-content.course-layout {
    display: block;
    padding: 16px;
  }

  .course-nav-pane {
    position: static;
    margin-bottom: 12px;
  }
}