:root {
  color-scheme: light;
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  --sf-canvas: #f2f2f2;
  --sf-surface: #ffffff;
  --sf-surface-subtle: #f7f7f7;
  --sf-ink: #171717;
  --sf-muted: #666666;
  --sf-line: #c9c9c9;
  --sf-strong-line: #8b8b8b;
  --sf-focus: #111111;
  --sf-radius-sm: 8px;
  --sf-radius-md: 14px;
  --sf-space-1: 4px;
  --sf-space-2: 8px;
  --sf-space-3: 12px;
  --sf-space-4: 16px;
  --sf-space-5: 24px;
  --sf-space-6: 32px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
  margin: 0;
}

body {
  min-width: 320px;
  background: var(--sf-canvas);
  color: var(--sf-ink);
}

button,
a {
  font: inherit;
}

button:focus-visible,
a:focus-visible {
  outline: 3px solid var(--sf-focus);
  outline-offset: 3px;
}

.sf-skeleton {
  min-height: 100vh;
}

.sf-shell {
  position: relative;
  width: 100%;
  min-height: 100vh;
  margin: 0 auto;
  background: var(--sf-surface);
}

.sf-shell[data-layout-mode="PORTRAIT_FIRST"] {
  max-width: 480px;
}

.sf-shell[data-layout-mode="SCREEN_FIRST"] {
  max-width: 1440px;
}

.sf-review-notice {
  margin: 0;
  padding: var(--sf-space-2) var(--sf-space-4);
  border-bottom: 1px solid var(--sf-line);
  background: var(--sf-surface-subtle);
  color: var(--sf-muted);
  font-size: 0.72rem;
  line-height: 1.4;
  text-align: center;
}

.sf-heading-group {
  min-width: 0;
}

.sf-eyebrow {
  margin: 0 0 var(--sf-space-2);
  color: var(--sf-muted);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.sf-title,
.sf-card-title,
.sf-supporting,
.sf-card-detail,
.sf-meta,
.sf-helper {
  margin-top: 0;
}

.sf-title {
  margin-bottom: var(--sf-space-2);
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  line-height: 1.05;
}

.sf-card-title {
  margin-bottom: var(--sf-space-2);
  font-size: 1.2rem;
  line-height: 1.2;
}

.sf-supporting,
.sf-card-detail,
.sf-helper {
  color: var(--sf-muted);
  line-height: 1.5;
}

.sf-supporting,
.sf-card-detail {
  margin-bottom: var(--sf-space-4);
}

.sf-helper {
  margin-bottom: 0;
  font-size: 0.78rem;
}

.sf-state-badge,
.sf-identity {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: var(--sf-space-1) var(--sf-space-3);
  border: 1px solid var(--sf-strong-line);
  border-radius: 999px;
  background: var(--sf-surface);
  color: var(--sf-ink);
  font-size: 0.72rem;
  font-weight: 700;
  white-space: nowrap;
}

.sf-meta-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--sf-space-2) var(--sf-space-4);
}

.sf-meta {
  margin-bottom: var(--sf-space-2);
  color: var(--sf-muted);
  font-size: 0.78rem;
}

.sf-progress {
  margin: var(--sf-space-2) 0 var(--sf-space-4);
}

.sf-progress__track {
  width: 100%;
  height: 6px;
  overflow: hidden;
  border-radius: 999px;
  background: var(--sf-line);
}

.sf-progress__fill {
  height: 100%;
  border-radius: inherit;
  background: var(--sf-ink);
}

.sf-action,
.sf-mode {
  min-height: 44px;
  border: 1px solid var(--sf-strong-line);
  border-radius: var(--sf-radius-sm);
  cursor: pointer;
}

.sf-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--sf-space-3) var(--sf-space-4);
  font-weight: 700;
}

.sf-action--primary {
  border-color: var(--sf-ink);
  background: var(--sf-ink);
  color: var(--sf-surface);
}

.sf-action--secondary,
.sf-mode {
  background: var(--sf-surface);
  color: var(--sf-ink);
}

.sf-asset-slot {
  position: relative;
  min-height: 180px;
  margin: 0;
  overflow: hidden;
  border: 1px dashed var(--sf-strong-line);
  border-radius: var(--sf-radius-md);
  background: var(--sf-surface-subtle);
}

.sf-asset,
.sf-asset-placeholder {
  width: 100%;
  height: 100%;
  min-height: inherit;
}

.sf-asset {
  display: block;
  object-fit: cover;
}

.sf-asset[hidden],
.sf-asset-placeholder[hidden] {
  display: none;
}

.sf-asset-placeholder {
  display: grid;
  place-items: center;
  padding: var(--sf-space-4);
  color: var(--sf-muted);
  font-size: 0.72rem;
  text-align: center;
}

.sf-today {
  display: flex;
  flex-direction: column;
}

.sf-today__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--sf-space-4);
  padding: var(--sf-space-6) var(--sf-space-5) var(--sf-space-4);
}

.sf-today__main {
  display: grid;
  gap: var(--sf-space-4);
  padding: 0 var(--sf-space-5) calc(76px + var(--sf-space-5));
}

.sf-primary-card,
.sf-supporting-card {
  border: 1px solid var(--sf-line);
  border-radius: var(--sf-radius-md);
  background: var(--sf-surface);
}

.sf-primary-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(120px, 0.7fr);
  gap: var(--sf-space-4);
  padding: var(--sf-space-4);
}

.sf-primary-card__copy {
  display: flex;
  min-width: 0;
  flex-direction: column;
  align-items: flex-start;
}

.sf-primary-card__copy .sf-action {
  margin-top: auto;
}

.sf-supporting-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--sf-space-3);
}

.sf-supporting-card {
  display: flex;
  min-width: 0;
  flex-direction: column;
  align-items: flex-start;
  padding: var(--sf-space-4);
}

.sf-supporting-card .sf-action {
  width: 100%;
  margin-top: auto;
}

.sf-nav {
  position: fixed;
  z-index: 2;
  right: 0;
  bottom: 0;
  left: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  max-width: 480px;
  min-height: 68px;
  margin: 0 auto;
  border-top: 1px solid var(--sf-line);
  background: var(--sf-surface);
}

.sf-nav__item {
  display: grid;
  place-items: center;
  min-width: 0;
  padding: var(--sf-space-2);
  color: var(--sf-muted);
  font-size: 0.74rem;
  text-decoration: none;
}

.sf-nav__item.is-active {
  color: var(--sf-ink);
  font-weight: 800;
  text-decoration: underline;
  text-underline-offset: 5px;
}

.sf-classroom {
  display: grid;
  grid-template-rows: auto auto auto minmax(0, 1fr) auto;
  min-height: 100vh;
}

.sf-classroom__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--sf-space-5);
  padding: var(--sf-space-4) var(--sf-space-5) var(--sf-space-3);
  border-bottom: 1px solid var(--sf-line);
}

.sf-classroom__status {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: var(--sf-space-2);
}

.sf-classroom__progress {
  padding: var(--sf-space-3) var(--sf-space-5) 0;
}

.sf-classroom__workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(240px, 0.28fr);
  gap: var(--sf-space-4);
  min-height: 0;
  padding: var(--sf-space-4) var(--sf-space-5);
}

.sf-classroom__stage,
.sf-classroom__side {
  min-width: 0;
  border: 1px solid var(--sf-line);
  border-radius: var(--sf-radius-md);
  background: var(--sf-surface);
}

.sf-classroom__stage {
  position: relative;
  display: grid;
  grid-template-columns: minmax(180px, 0.42fr) minmax(0, 1fr);
  grid-template-rows: minmax(180px, 1fr) auto;
  gap: var(--sf-space-4);
  overflow: hidden;
  padding: var(--sf-space-4);
}

.sf-scene-slot {
  position: absolute;
  inset: var(--sf-space-4);
  min-height: 0;
  opacity: 0.25;
}

.sf-teacher-slot {
  z-index: 1;
  grid-row: 1;
  min-height: 240px;
}

.sf-dialogue {
  z-index: 1;
  display: grid;
  align-content: center;
  gap: var(--sf-space-3);
  grid-column: 2;
  grid-row: 1;
  margin: 0;
  padding: 0;
  list-style: none;
}

.sf-dialogue__turn {
  padding: var(--sf-space-3) var(--sf-space-4);
  border: 1px solid var(--sf-line);
  border-radius: var(--sf-radius-md);
  background: var(--sf-surface);
}

.sf-dialogue__speaker,
.sf-dialogue__support,
.sf-dialogue__translation {
  color: var(--sf-muted);
  font-size: 0.76rem;
}

.sf-dialogue__speaker {
  font-weight: 800;
}

.sf-dialogue__text {
  margin: var(--sf-space-2) 0;
  font-size: clamp(1.15rem, 2.6vw, 1.65rem);
  line-height: 1.3;
}

.sf-dialogue__support,
.sf-dialogue__translation {
  margin: var(--sf-space-1) 0 0;
}

.sf-classroom__side {
  padding: var(--sf-space-4);
}

.sf-signal-list {
  display: grid;
  gap: var(--sf-space-2);
  margin: var(--sf-space-5) 0 0;
  padding: 0;
  list-style: none;
}

.sf-signal-list__item {
  padding: var(--sf-space-2) 0;
  border-top: 1px solid var(--sf-line);
  color: var(--sf-muted);
  font-size: 0.78rem;
}

.sf-classroom__controls {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--sf-space-4);
  padding: var(--sf-space-3) var(--sf-space-5) var(--sf-space-4);
  border-top: 1px solid var(--sf-line);
}

.sf-mode-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sf-space-2);
}

.sf-mode {
  padding: var(--sf-space-2) var(--sf-space-4);
}

.sf-mode.is-selected {
  border-color: var(--sf-ink);
  background: var(--sf-ink);
  color: var(--sf-surface);
}

.sf-primary-control {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--sf-space-3);
}

.sf-primary-control__helper {
  max-width: 220px;
}

@media (max-width: 760px) {
  .sf-today__header,
  .sf-classroom__header {
    align-items: stretch;
    flex-direction: column;
  }

  .sf-primary-card,
  .sf-supporting-grid,
  .sf-classroom__workspace,
  .sf-classroom__controls {
    grid-template-columns: 1fr;
  }

  .sf-primary-card .sf-asset-slot {
    order: -1;
    min-height: 160px;
  }

  .sf-classroom__workspace,
  .sf-classroom__header,
  .sf-classroom__progress,
  .sf-classroom__controls {
    padding-right: var(--sf-space-4);
    padding-left: var(--sf-space-4);
  }

  .sf-classroom__stage {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto;
  }

  .sf-teacher-slot,
  .sf-dialogue {
    grid-column: 1;
  }

  .sf-teacher-slot {
    grid-row: 1;
    min-height: 180px;
  }

  .sf-dialogue {
    grid-row: 2;
  }

  .sf-primary-control {
    align-items: stretch;
    flex-direction: column;
  }

  .sf-primary-control .sf-action {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (forced-colors: active) {
  .sf-progress__fill,
  .sf-action--primary,
  .sf-mode.is-selected {
    forced-color-adjust: none;
    background: CanvasText;
    color: Canvas;
  }
}