/* ── Reset & Base ─────────────────────────────────────── */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --color-bg: #0f1117;
  --color-surface: #1a1d27;
  --color-surface-hover: #222632;
  --color-border: #2a2e3a;
  --color-text: #e4e6ed;
  --color-text-muted: #8b8fa3;
  --color-accent: #6c5ce7;
  --color-accent-hover: #7c6ef7;
  --color-accent-glow: rgba(108, 92, 231, 0.15);
  --color-success: #2ed573;
  --color-danger: #ff4757;
  --radius: 10px;
  --radius-lg: 16px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', monospace;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --transition: 150ms ease;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100vh;
  line-height: 1.6;
}

/* ── Layout ──────────────────────────────────────────── */

.page {
  min-width: 320px;
  margin: 0 auto;
  padding: 48px clamp(24px, 5vw, 120px) 64px;
}

/* ── Index Page ──────────────────────────────────────── */

.page-header {
  margin-bottom: 24px;
}

.page-header__title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, var(--color-accent), #a29bfe);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.page-header__subtitle {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin-top: 6px;
}

.section {
  margin-bottom: 40px;
}

.section__title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: 12px;
  padding-left: 4px;
}

.card-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.card-link {
  display: block;
  padding: 16px 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--color-text);
  transition: background var(--transition), border-color var(--transition),
    box-shadow var(--transition);
}

.card-link:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.card-link__name {
  font-weight: 600;
  font-size: 0.95rem;
}

.card-link__desc {
  color: var(--color-text-muted);
  font-size: 0.82rem;
  margin-top: 4px;
}

.section p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  line-height: 1.55;
  margin: 0 0 12px 4px;
}

.section ul {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  line-height: 1.55;
  margin: 0 0 12px 4px;
  padding-left: 1.2em;
}

.section li {
  margin-bottom: 6px;
}

.section strong {
  color: var(--color-text);
  font-weight: 600;
}

.section a {
  color: var(--color-accent-hover);
  text-decoration: none;
}

.section a:hover {
  text-decoration: underline;
}

/* ── Demo Page ───────────────────────────────────────── */

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  transition: color var(--transition);
  margin-top: 8px;
}

.back-link:hover {
  color: var(--color-accent-hover);
}

.back-link__arrow {
  font-size: 1.1em;
  line-height: 1;
}

/* ── Demo Description (rendered markdown) ───────────── */

.demo-description:empty {
  display: none;
}

.demo-description {
  margin-bottom: 20px;
  line-height: 1.7;
  color: var(--color-text);
  font-size: 0.9rem;
}

.demo-description h1,
.demo-description h2,
.demo-description h3 {
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-top: 1.2em;
  margin-bottom: 0.5em;
}

.demo-description h1:first-child,
.demo-description h2:first-child,
.demo-description h3:first-child {
  margin-top: 0;
}

.demo-description h1 { font-size: 1.2rem; }
.demo-description h2 { font-size: 1.05rem; }
.demo-description h3 { font-size: 0.95rem; }

.demo-description p {
  margin: 0.6em 0;
}

.demo-description ul,
.demo-description ol {
  margin: 0.6em 0;
  padding-left: 1.5em;
}

.demo-description li {
  margin: 0.3em 0;
}

.demo-description code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 0.15em 0.4em;
}

.demo-description pre {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 16px;
  overflow-x: auto;
  margin: 0.8em 0;
}

.demo-description pre code {
  background: none;
  border: none;
  padding: 0;
}

.demo-description a {
  color: var(--color-accent);
  text-decoration: none;
}

.demo-description a:hover {
  color: var(--color-accent-hover);
  text-decoration: underline;
}

.demo-description strong {
  font-weight: 600;
}

/* ── Panel (the main controls area) ──────────────────── */

.panel {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.panel__section {
  padding: 16px 0;
  border-bottom: 1px solid var(--color-border);
}

.panel__section:first-child,
.loading-overlay + .panel__section {
  padding-top: 0;
}

.panel__section:last-child {
  padding-bottom: 0;
  border-bottom: none;
}

/* ── Loading overlay ─────────────────────────────────── */

.loading-overlay {
  position: absolute;
  inset: 0;
  z-index: 10;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  background: rgba(26, 29, 39, 0.85);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  border-radius: var(--radius-lg);
}

.loading-overlay__spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.loading-overlay__text {
  color: var(--color-text-muted);
  font-size: 0.85rem;
  font-weight: 500;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* ── Buttons ─────────────────────────────────────────── */

.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 20px;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 600;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface-hover);
  color: var(--color-text);
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}

.btn:hover:not(:disabled) {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.btn:active:not(:disabled) {
  transform: scale(0.97);
}

.btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.btn--primary {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}

.btn--primary:hover:not(:disabled) {
  background: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
}

.btn--sm {
  padding: 7px 14px;
  font-size: 0.8rem;
}

/* ── Worker controls ─────────────────────────────────── */

.worker-controls {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.worker-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.worker-badge__count {
  color: var(--color-text);
  font-weight: 700;
  font-family: var(--font-mono);
}

/* ── Slider / Range ──────────────────────────────────── */

.slider-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.slider-group__label {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.slider-group__value {
  color: var(--color-text);
  font-family: var(--font-mono);
  font-weight: 600;
}

.slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  max-width: 280px;
  height: 6px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 3px;
  outline: none;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--color-accent);
  border: 2px solid var(--color-surface);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: box-shadow var(--transition);
}

.slider::-webkit-slider-thumb:hover {
  box-shadow: 0 0 0 4px var(--color-accent-glow);
}

.slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--color-accent);
  border: 2px solid var(--color-surface);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
}

/* ── Source Code Panel ───────────────────────────────── */

.source-code-panel {
  margin-top: 20px;
}

.source-code-panel__title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.source-tabs {
  display: flex;
  gap: 2px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 0;
}

.source-tab {
  padding: 8px 16px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--color-text-muted);
  background: none;
  border: 1px solid transparent;
  border-bottom: none;
  border-radius: 6px 6px 0 0;
  cursor: pointer;
  transition: color var(--transition), background var(--transition);
}

.source-tab:hover {
  color: var(--color-text);
  background: var(--color-surface-hover);
}

.source-tab--active {
  color: var(--color-text);
  background: var(--color-bg);
  border-color: var(--color-border);
}

.source-code-container pre {
  margin: 0;
  padding: 16px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 0 0 8px 8px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.6;
}

/* When there are no tabs, round all corners */
.source-code-container:first-child pre {
  border-radius: 8px;
}

.source-code-container code.hljs {
  background: transparent;
  padding: 0;
}

/* Line numbers (highlightjs-line-numbers.js) */
.hljs-ln {
  border-collapse: collapse;
}

.hljs-ln td {
  padding: 0;
}

.hljs-ln-numbers {
  user-select: none;
  text-align: right;
  padding-right: 16px !important;
  color: var(--color-text-muted);
  opacity: 0.4;
  vertical-align: top;
  width: 1%;
  white-space: nowrap;
}

/* ── Responsive ──────────────────────────────────────── */

@media (max-width: 480px) {
  .page {
    padding: 32px 16px 48px;
  }

  .page-header__title {
    font-size: 1.6rem;
  }

  .demo-header__title {
    font-size: 1.25rem;
  }

  .panel {
    padding: 16px;
  }

  .btn-group {
    flex-direction: column;
    align-items: stretch;
  }

  .worker-controls {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ── Video demo (hand tracking) ──────────────────────── */

.video-canvas {
  display: block;
  width: 100%;
  border-radius: 8px;
  background: #000;
  border: 1px solid var(--color-border);
}

.indicators {
  display: flex;
  gap: 10px;
  margin-top: 14px;
}

.indicator {
  flex: 1;
  min-width: 0;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 8px 12px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.indicator--hand {
  flex: 1.5;
}

.indicator__label {
  font-size: 0.68rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  white-space: nowrap;
  overflow: hidden;
}

.indicator__value {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.controls-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 20px 28px;
}

.loading-overlay--error .loading-overlay__spinner {
  display: none;
}

.loading-overlay--error .loading-overlay__text {
  color: var(--color-danger);
}

@media (max-width: 640px) {
  .indicators {
    flex-wrap: wrap;
  }

  .indicator {
    flex-basis: 30%;
  }
}

/* The design's display rules would otherwise override the hidden attribute */
[hidden] {
  display: none !important;
}