/* =========================================================
   SignSpeak — design system
   Palette: light Material-ish surfaces, YouTube-inspired red
   accent, restrained clay elevation. No gradients as primary
   treatment, no purple/blue AI look.
   ========================================================= */

:root {
  --background: #f2f2f3;
  --surface: #ffffff;
  --surface-elevated: #ffffff;
  --surface-sunken: #e9e9eb;
  --ink: #0f0f0f;
  --text-primary: #0f0f0f;
  --text-secondary: #5b5b5f;
  --text-tertiary: #8a8a8e;
  --border: #e2e2e5;
  --border-strong: #cfcfd3;
  --accent: #c4001a;
  --accent-ink: #ffffff;
  --accent-tint: #fbe6e9;
  --accent-dark: #960014;
  --success: #1a7d3f;
  --success-tint: #e5f5eb;
  --warning: #9a5b00;
  --warning-tint: #fdf1e0;

  --shadow-1: 0 1px 2px rgba(15, 15, 15, 0.06), 0 1px 1px rgba(15, 15, 15, 0.04);
  --shadow-2: 0 2px 6px rgba(15, 15, 15, 0.08), 0 1px 2px rgba(15, 15, 15, 0.05);
  --shadow-3: 0 8px 24px rgba(15, 15, 15, 0.12), 0 2px 6px rgba(15, 15, 15, 0.06);
  --shadow-clay: inset 0 1px 0 rgba(255, 255, 255, 0.6), inset 0 -2px 3px rgba(15, 15, 15, 0.05), 0 1px 2px rgba(15, 15, 15, 0.08);

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;

  --header-h: 56px;
  --font-ui: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #0f0f10;
    --surface: #1b1b1d;
    --surface-elevated: #202022;
    --surface-sunken: #141415;
    --ink: #f2f2f2;
    --text-primary: #f2f2f2;
    --text-secondary: #a7a7ab;
    --text-tertiary: #7c7c80;
    --border: #2c2c2e;
    --border-strong: #3a3a3c;
    --accent: #ff2d43;
    --accent-tint: #33141a;
    --accent-dark: #ff5468;
    --success: #4cc47f;
    --success-tint: #113322;
    --warning: #e0a437;
    --warning-tint: #33270e;
    --shadow-clay: inset 0 1px 0 rgba(255, 255, 255, 0.04), inset 0 -2px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.5);
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--background);
  color: var(--text-primary);
  font-family: var(--font-ui);
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  padding-top: var(--header-h);
}

h1, h2, h3 { font-weight: 700; margin: 0; letter-spacing: -0.01em; }
p { margin: 0; }
ul, ol, dl { margin: 0; padding: 0; list-style: none; }
dd { margin: 0; }
button { font-family: inherit; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 10px 16px;
  border-radius: 0 0 8px 0;
  z-index: 100;
}
.skip-link:focus {
  left: 0;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ===================== HEADER ===================== */

.topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 16px;
  z-index: 50;
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
}

.logo-mark {
  display: inline-flex;
  color: var(--accent);
  flex-shrink: 0;
}

.logo-text {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.logo-tag {
  font-size: 0.68rem;
  color: var(--text-tertiary);
  border: 1px solid var(--border-strong);
  border-radius: 5px;
  padding: 1px 6px;
  white-space: nowrap;
  display: none;
}

.topbar-center {
  display: flex;
  justify-content: center;
  min-width: 0;
}

.topbar-hint {
  font-size: 0.82rem;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.topbar-right {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 10px;
}

.cam-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  color: var(--text-secondary);
  background: var(--surface-sunken);
  border-radius: 100px;
  padding: 5px 10px 5px 8px;
  white-space: nowrap;
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--text-tertiary);
  flex-shrink: 0;
}
.dot-off { background: var(--text-tertiary); }
.dot-on {
  background: var(--success);
  box-shadow: 0 0 0 3px var(--success-tint);
}
.dot-warn { background: var(--warning); box-shadow: 0 0 0 3px var(--warning-tint); }

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-primary);
  cursor: pointer;
}
.icon-btn:hover { background: var(--surface-sunken); }

/* ===================== BUTTONS ===================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  font-weight: 600;
  padding: 9px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text-primary);
  cursor: pointer;
  box-shadow: var(--shadow-clay);
  transition: transform 0.08s ease, box-shadow 0.08s ease;
}
.btn:hover { background: var(--surface-sunken); }
.btn:active { transform: translateY(1px); box-shadow: var(--shadow-1); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; box-shadow: none; }

.btn-primary {
  background: var(--accent);
  border-color: var(--accent-dark);
  color: var(--accent-ink);
}
.btn-primary:hover { background: var(--accent-dark); }
.btn-primary[aria-pressed="true"] {
  background: var(--surface);
  color: var(--accent);
  border-color: var(--accent);
}

.btn-ghost {
  background: transparent;
  box-shadow: none;
  border-color: var(--border-strong);
}
.btn-ghost:hover { background: var(--surface-sunken); }

.btn-speak { width: 100%; justify-content: center; }
.action-row { display: flex; gap: 10px; }
.action-row .btn-ghost { flex: 0 0 auto; }
.action-row .btn-speak { flex: 1; }

/* ===================== LAYOUT ===================== */

main {
  max-width: 1320px;
  margin: 0 auto;
  padding: 24px 24px 64px;
}

.app-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(320px, 1fr);
  gap: 20px;
  align-items: start;
}

/* ===================== CAMERA PANEL ===================== */

.camera-panel {
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-2);
  padding: 16px;
}

.panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.panel-head h2 { font-size: 1rem; }

.video-stage {
  position: relative;
  width: 100%;
  aspect-ratio: 4 / 3;
  background: #17181a;
  border-radius: var(--radius-md);
  overflow: hidden;
}

#video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transform: scaleX(-1);
}

#overlay {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  transform: scaleX(-1);
}

.stage-badge {
  position: absolute;
  left: 12px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 600;
  color: #fff;
  background: rgba(15, 15, 15, 0.55);
  backdrop-filter: blur(6px);
  padding: 6px 10px;
  border-radius: 100px;
  z-index: 3;
}
.stage-badge-top { top: 12px; }
.stage-badge-bottom {
  bottom: 12px;
  left: 12px;
  right: 12px;
  justify-content: center;
  text-align: center;
}

.stage-empty {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  color: #c7c8ca;
  text-align: center;
  padding: 24px;
  z-index: 2;
}
.stage-empty p { max-width: 280px; font-size: 0.9rem; }

.stage-error {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background: rgba(15, 15, 15, 0.92);
  color: #ffd9dd;
  text-align: center;
  padding: 24px;
  z-index: 4;
}
.stage-error p { max-width: 320px; font-size: 0.9rem; line-height: 1.4; }

.stage-footnote {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-tertiary);
}

/* ===================== TRANSLATE PANEL ===================== */

.translate-panel {
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-2);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.translate-panel h2 { font-size: 1rem; }

.word-card {
  background: var(--surface-sunken);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-clay);
  padding: 20px 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.word-state {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.word-display {
  font-size: 2.6rem;
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  word-break: break-word;
  transition: opacity 0.15s ease;
}
.word-display .quote { color: var(--text-tertiary); font-weight: 400; }

.confidence-row {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.78rem;
  color: var(--text-secondary);
}
.confidence-track {
  flex: 1;
  height: 6px;
  background: var(--border);
  border-radius: 100px;
  overflow: hidden;
}
.confidence-fill {
  height: 100%;
  width: 0%;
  background: var(--accent);
  border-radius: 100px;
  transition: width 0.2s ease;
}
#confidenceValue { font-family: var(--font-mono); min-width: 34px; text-align: right; }

.gesture-caption {
  font-size: 0.82rem;
  color: var(--text-secondary);
}
.gesture-caption strong { color: var(--text-primary); }

.history-block h3 {
  font-size: 0.82rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
  font-weight: 600;
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.history-list li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.86rem;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  background: var(--surface-sunken);
}
.history-list li span.hist-time {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-tertiary);
}
.history-empty {
  color: var(--text-tertiary) !important;
  background: transparent !important;
  padding: 4px 2px !important;
  font-size: 0.82rem !important;
}

/* ===================== STATUS PANEL ===================== */

.status-panel {
  margin-top: 20px;
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-1);
  overflow: hidden;
}

.status-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 13px 16px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
}
.status-toggle .chev { transition: transform 0.15s ease; color: var(--text-secondary); }
.status-toggle[aria-expanded="true"] .chev { transform: rotate(180deg); }

.status-body {
  padding: 4px 16px 16px;
  border-top: 1px solid var(--border);
}

.status-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-top: 12px;
}
.status-grid dt {
  font-size: 0.68rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 3px;
}
.status-grid dd {
  font-family: var(--font-mono);
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* ===================== GUIDE ===================== */

.guide-section { margin-top: 40px; }
.guide-section h2 { font-size: 1.1rem; margin-bottom: 6px; }
.guide-note {
  font-size: 0.85rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin-bottom: 18px;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
}

.guide-card {
  background: var(--surface-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-clay);
  padding: 16px 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 6px;
}
.guide-emoji { font-size: 1.8rem; }
.guide-word { font-weight: 700; font-size: 0.9rem; letter-spacing: 0.02em; }
.guide-desc { font-size: 0.75rem; color: var(--text-secondary); }

/* ===================== NEXT ===================== */

.next-section {
  margin-top: 40px;
  padding-top: 28px;
  border-top: 1px solid var(--border);
}
.next-section h2 { font-size: 1.1rem; margin-bottom: 6px; }
.next-intro {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 14px;
  max-width: 640px;
}
.next-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 24px;
  max-width: 900px;
}
.next-list li {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
  padding-left: 14px;
  border-left: 2px solid var(--border-strong);
}
.next-list li strong { color: var(--text-primary); font-weight: 600; }

/* ===================== FOOTER ===================== */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 20px 24px 32px;
  text-align: center;
}
.site-footer p {
  font-size: 0.78rem;
  color: var(--text-tertiary);
  max-width: 520px;
  margin: 0 auto;
}

/* ===================== TOAST ===================== */

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translate(-50%, 12px);
  background: var(--ink);
  color: var(--background);
  font-size: 0.85rem;
  padding: 10px 18px;
  border-radius: 100px;
  box-shadow: var(--shadow-3);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  z-index: 80;
  max-width: 90vw;
  text-align: center;
}
.toast.show {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* ===================== RESPONSIVE ===================== */

@media (max-width: 1000px) {
  .app-grid {
    grid-template-columns: 1fr;
  }
  .logo-tag { display: inline-block; }
  .next-list { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .topbar-center { display: none; }
  .topbar { grid-template-columns: auto auto; justify-content: space-between; }
  main { padding: 16px 14px 48px; }
  .word-display { font-size: 2.1rem; }
  .status-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .cam-pill span:not(.dot) { display: none; }
}

@media (max-width: 420px) {
  .logo-tag { display: none; }
}

/* ===================== MOTION ===================== */

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

.pulse-once {
  animation: pulseOnce 0.4s ease;
}
@keyframes pulseOnce {
  0% { transform: scale(1); }
  40% { transform: scale(1.04); }
  100% { transform: scale(1); }
}