:root {
  color-scheme: light;
  --page: #f5f6f8;
  --surface: #ffffff;
  --surface-soft: #faf7f3;
  --ink: #18212f;
  --muted: #697386;
  --line: #dfe3e8;
  --accent: #b52d2a;
  --accent-strong: #8f201e;
  --accent-soft: #fff0ed;
  --focus: #2457d6;
  --success: #18734b;
  --danger: #a52222;
  --shadow: 0 18px 45px rgba(31, 42, 68, 0.08);
  --radius-large: 22px;
  --radius-medium: 15px;
  --radius-small: 11px;
  --content-width: 900px;
  --transcript-scale: 1;
  --audio-dock-height: 122px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--page);
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at top right, rgba(181, 45, 42, 0.09), transparent 29rem),
    var(--page);
  line-height: 1.55;
}

button,
select,
input {
  font: inherit;
}

button,
select,
input,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  color: var(--ink);
  background: var(--surface);
  cursor: pointer;
  transition: border-color 140ms ease, background-color 140ms ease, color 140ms ease, transform 140ms ease;
}

button:hover {
  border-color: #b8c0cb;
}

button:active {
  transform: translateY(1px);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.42;
  transform: none;
}

button:focus-visible,
select:focus-visible,
input:focus-visible,
a:focus-visible,
audio:focus-visible,
video:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--focus) 34%, transparent);
  outline-offset: 2px;
}

a {
  color: var(--accent-strong);
  text-underline-offset: 0.18em;
}

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  padding-top: env(safe-area-inset-top);
  border-bottom: 1px solid rgba(223, 227, 232, 0.9);
  background: rgba(245, 246, 248, 0.9);
  backdrop-filter: blur(16px);
}

.header-inner {
  display: flex;
  width: min(calc(100% - 28px), var(--content-width));
  min-height: 70px;
  margin: 0 auto;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: inherit;
  text-decoration: none;
}

.brand img {
  display: block;
  flex: 0 0 auto;
  border-radius: 12px;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  line-height: 1.2;
}

.brand small {
  margin-top: 2px;
  color: var(--muted);
  font-size: 0.73rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.mvp-badge {
  padding: 5px 10px;
  border: 1px solid color-mix(in srgb, var(--accent) 30%, var(--line));
  border-radius: 999px;
  color: var(--accent-strong);
  background: var(--accent-soft);
  font-size: 0.7rem;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.page-shell {
  width: min(calc(100% - 24px), var(--content-width));
  margin: 0 auto;
  padding: 28px 0 calc(46px + env(safe-area-inset-bottom));
}

.card {
  margin-bottom: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-large);
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--shadow);
}

.lesson-card {
  padding: clamp(18px, 4vw, 28px);
}

.lesson-nav {
  display: grid;
  grid-template-columns: minmax(86px, 1fr) minmax(0, 1.65fr) minmax(86px, 1fr);
  gap: 10px;
  align-items: center;
  margin-bottom: 24px;
}

.lesson-nav > :last-child {
  justify-self: stretch;
}

.lesson-select-label,
.lesson-select-label select {
  min-width: 0;
  width: 100%;
}

.lesson-select-label select {
  min-height: 44px;
  padding: 0 34px 0 11px;
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  color: var(--ink);
  background: var(--surface);
  text-overflow: ellipsis;
}

.lesson-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
}

.eyebrow {
  margin: 0;
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.lesson-heading h1 {
  max-width: 21ch;
  margin: 5px 0 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2rem, 7vw, 3.7rem);
  line-height: 1.05;
  letter-spacing: -0.035em;
}

.complete-control {
  display: inline-flex;
  min-height: 42px;
  padding: 0 12px;
  align-items: center;
  gap: 7px;
  flex: 0 0 auto;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  background: var(--surface-soft);
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 700;
}

.complete-control input {
  width: 17px;
  height: 17px;
  accent-color: var(--success);
}

.source-line {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 0.84rem;
}

.media-card,
.transcript-card {
  padding: clamp(18px, 4vw, 28px);
}

.section-heading-row {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 17px;
}

.section-heading-row h2 {
  margin: 3px 0 0;
  font-size: clamp(1.35rem, 4vw, 1.72rem);
  line-height: 1.2;
}

.mode-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-width: 154px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: var(--surface-soft);
}

.mode-tab {
  min-height: 38px;
  padding: 0 15px;
  border-color: transparent;
  background: transparent;
  font-weight: 800;
}

.mode-tab[aria-selected="true"] {
  border-color: var(--line);
  color: var(--accent-strong);
  background: var(--surface);
  box-shadow: 0 3px 10px rgba(31, 42, 68, 0.07);
}

.media-panel {
  padding: 15px;
  border-radius: var(--radius-medium);
  background: #111827;
}

.media-panel[hidden] {
  display: none;
}

.media-tip {
  margin: 0 0 11px;
  color: #c9d2e2;
  font-size: 0.8rem;
}

.media-panel audio,
.media-panel video {
  display: block;
  width: 100%;
}

.media-panel audio {
  min-height: 54px;
}

.media-panel video {
  max-height: 64vh;
  border-radius: 9px;
  background: #05070c;
}

.notice {
  margin: 0 0 16px;
  padding: 13px 15px;
  border: 1px solid #e5c96f;
  border-radius: var(--radius-small);
  color: #685113;
  background: #fff9df;
  font-size: 0.86rem;
}

.notice.compact {
  margin: 12px 0 0;
}

.notice-error {
  border-color: #e5aaaa;
  color: var(--danger);
  background: #fff0f0;
}

.control-grid {
  display: grid;
  gap: 16px;
  margin-top: 20px;
}

.control-block,
.timer-block {
  padding: 17px;
  border: 1px solid var(--line);
  border-radius: var(--radius-medium);
  background: var(--surface-soft);
}

.control-block h3,
.timer-block h3 {
  margin: 0;
  font-size: 0.96rem;
}

.control-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}

.control-title-row output {
  color: var(--accent-strong);
  font-variant-numeric: tabular-nums;
  font-weight: 800;
}

.chip-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
}

.chip {
  min-width: 0;
  padding: 0 8px;
  font-size: 0.86rem;
  font-weight: 750;
}

.chip.is-active,
.chip[aria-pressed="true"] {
  border-color: var(--accent);
  color: var(--accent-strong);
  background: var(--accent-soft);
}

.stepper-row {
  display: grid;
  grid-template-columns: 50px 1fr 50px;
  gap: 8px;
  align-items: center;
  margin-top: 10px;
  color: var(--muted);
  text-align: center;
  font-size: 0.78rem;
}

.square-button {
  width: 50px;
  padding: 0;
  font-weight: 800;
}

.secondary-button {
  padding: 0 12px;
  color: #4d5869;
  background: var(--surface);
  font-weight: 700;
}

.action-row {
  display: grid;
  grid-template-columns: minmax(90px, 1fr) minmax(150px, 1.5fr) minmax(90px, 1fr);
  gap: 8px;
  margin-top: 12px;
}

.toggle-button {
  padding: 0 12px;
  font-weight: 800;
}

.toggle-button[aria-pressed="true"] {
  border-color: color-mix(in srgb, var(--success) 48%, var(--line));
  color: var(--success);
  background: color-mix(in srgb, var(--success) 8%, white);
}

.timer-block {
  margin-top: 16px;
}

.subtle {
  margin: 3px 0 0;
  color: var(--muted);
  font-size: 0.78rem;
}

.custom-timer-row {
  display: grid;
  grid-template-columns: auto minmax(74px, 1fr) auto auto;
  gap: 8px;
  align-items: center;
  margin-top: 11px;
}

.custom-timer-row label {
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 700;
}

.custom-timer-row input {
  width: 100%;
  min-width: 0;
  min-height: 44px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius-small);
  color: var(--ink);
  background: var(--surface);
}

.text-button {
  padding: 0 10px;
  border-color: transparent;
  color: var(--accent-strong);
  background: transparent;
  font-weight: 750;
}

.transcript-heading-row {
  align-items: center;
}

.font-controls {
  display: flex;
  gap: 8px;
}

.transcript-note {
  margin: -3px 0 0;
  color: var(--muted);
  font-size: 0.8rem;
}

.transcript {
  display: grid;
  margin-top: 16px;
}

.transcript-entry {
  display: grid;
  grid-template-columns: minmax(86px, 126px) minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--line);
}

.transcript-entry:first-child {
  border-top: 0;
}

.transcript-entry.is-note {
  display: block;
  padding: 14px;
  border: 0;
  border-radius: 12px;
  color: var(--muted);
  background: var(--surface-soft);
  font-style: italic;
}

.transcript-speaker {
  padding-top: 0.15em;
  color: var(--accent-strong);
  font-size: calc(0.86rem * var(--transcript-scale));
  font-weight: 850;
}

.transcript-text {
  min-width: 0;
  margin: 0;
  overflow-wrap: anywhere;
  font-family: Georgia, "Times New Roman", serif;
  font-size: calc(1.08rem * var(--transcript-scale));
  line-height: 1.74;
}

.site-footer {
  max-width: 68ch;
  margin: 28px auto 0;
  color: var(--muted);
  font-size: 0.77rem;
  text-align: center;
}

.toast {
  position: fixed;
  z-index: 50;
  right: 14px;
  bottom: calc(14px + env(safe-area-inset-bottom));
  left: 14px;
  max-width: 520px;
  margin: 0 auto;
  padding: 13px 16px;
  border-radius: 13px;
  color: #fff;
  background: rgba(24, 33, 47, 0.96);
  box-shadow: 0 14px 36px rgba(23, 32, 51, 0.3);
  font-size: 0.86rem;
  font-weight: 700;
  text-align: center;
}

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

[hidden] {
  display: none !important;
}

@media (min-width: 760px) {
  .page-shell {
    padding-top: 38px;
  }

  .control-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 620px) {
  .header-inner {
    min-height: 64px;
  }

  .brand small {
    display: none;
  }

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

  .lesson-select-label {
    grid-column: 1 / -1;
    grid-row: 1;
  }

  .lesson-nav #previousLesson,
  .lesson-nav #nextLesson {
    grid-row: 2;
  }

  .lesson-heading {
    display: block;
  }

  .complete-control {
    margin-top: 16px;
  }

  .section-heading-row {
    align-items: flex-start;
  }

  .mode-tabs {
    min-width: 142px;
  }

  .chip-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .action-row {
    grid-template-columns: 1fr 1fr;
  }

  .action-row .toggle-button {
    grid-column: 1 / -1;
    grid-row: 1;
  }

  .custom-timer-row {
    grid-template-columns: auto minmax(70px, 1fr) auto;
  }

  .custom-timer-row .text-button {
    grid-column: 1 / -1;
  }

  .transcript-entry {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .transcript-speaker {
    padding-top: 0;
  }
}

@media (max-width: 390px) {
  .page-shell {
    width: min(calc(100% - 18px), var(--content-width));
  }

  .media-card,
  .transcript-card,
  .lesson-card {
    padding: 16px;
    border-radius: 18px;
  }

  .section-heading-row {
    display: block;
  }

  .mode-tabs {
    width: 100%;
    margin-top: 12px;
  }
}

.audio-dock-slot {
  min-height: 54px;
}

.audio-dock {
  width: 100%;
}

.audio-dock-toolbar {
  display: none;
}

.audio-dock-title {
  min-width: 0;
  margin: 0;
  overflow: hidden;
  color: #f8fafc;
  font-size: 0.84rem;
  font-weight: 800;
  line-height: 1.2;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.audio-dock-actions {
  display: flex;
  flex: 0 0 auto;
  gap: 7px;
}

.audio-dock-skip {
  min-width: 50px;
  min-height: 36px;
  padding: 0 9px;
  border-color: rgba(255, 255, 255, 0.22);
  border-radius: 9px;
  color: #f8fafc;
  background: rgba(255, 255, 255, 0.1);
  font-size: 0.82rem;
  font-weight: 800;
}

.audio-dock-skip:hover {
  border-color: rgba(255, 255, 255, 0.42);
}

@media (max-width: 620px) {
  .audio-dock.is-docked {
    position: fixed;
    z-index: 45;
    right: 0;
    bottom: 0;
    left: 0;
    padding:
      9px max(12px, env(safe-area-inset-right))
      calc(10px + env(safe-area-inset-bottom))
      max(12px, env(safe-area-inset-left));
    border-top: 1px solid rgba(255, 255, 255, 0.16);
    background: rgba(17, 24, 39, 0.97);
    box-shadow: 0 -14px 34px rgba(17, 24, 39, 0.28);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
  }

  .audio-dock.is-docked .audio-dock-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 7px;
  }

  .audio-dock.is-docked audio {
    min-height: 48px;
  }

  body.has-audio-dock .page-shell {
    padding-bottom: calc(var(--audio-dock-height) + 42px);
  }

  body.has-audio-dock .toast {
    bottom: calc(var(--audio-dock-height) + 14px);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}