:root {
  --bg: #0f1419;
  --bg-elevated: #1a2332;
  --bg-card: #1e2a3a;
  --border: #2d3a4d;
  --text: #e8edf4;
  --text-muted: #9aa8bc;
  --accent: #3b9ddd;
  --accent-hover: #5eb3ef;
  --sidebar-width: 260px;
  --header-height: 56px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "Cascadia Code", "SF Mono", Menlo, monospace;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

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

a:hover {
  color: var(--accent-hover);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(15, 20, 25, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.25rem;
  height: 100%;
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.brand {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
  white-space: nowrap;
}

.header-links {
  display: flex;
  gap: 1.25rem;
  margin-left: auto;
}

.header-links a {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.header-links a:hover {
  color: var(--text);
}

.sidebar-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 1.25rem;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  cursor: pointer;
}

/* Hero */
.hero {
  background: linear-gradient(160deg, #152238 0%, var(--bg) 60%);
  border-bottom: 1px solid var(--border);
  padding: 3rem 1.25rem 3.5rem;
}

.hero-inner {
  max-width: 720px;
  margin: 0 auto;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.75rem;
  color: var(--accent);
  margin: 0 0 0.75rem;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.35rem);
  line-height: 1.2;
  margin: 0 0 1rem;
  font-weight: 700;
}

.lead {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin: 0 0 1.75rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-block;
  padding: 0.6rem 1.1rem;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 600;
  border: 1px solid transparent;
  transition: background 0.15s, border-color 0.15s;
}

.btn-primary {
  background: var(--accent);
  color: #0f1419;
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: #0f1419;
}

.btn-secondary {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Videos */
.videos {
  padding: 3rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: rgba(26, 35, 50, 0.35);
}

.section-lead {
  margin: -0.5rem 0 1.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.videos h2 {
  margin: 0 0 0.5rem;
  font-size: 1.35rem;
}

.video-featured {
  display: grid;
  grid-template-columns: minmax(240px, 420px) 1fr;
  gap: 1.5rem;
  align-items: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
  color: inherit;
  transition: border-color 0.15s;
}

.video-featured:hover {
  border-color: var(--accent);
  color: inherit;
}

.video-thumb {
  position: relative;
  border-radius: 8px;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background: var(--bg-elevated);
}

.video-thumb img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.video-play {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  color: #fff;
  background: rgba(0, 0, 0, 0.35);
  transition: background 0.15s;
}

.video-featured:hover .video-play {
  background: rgba(0, 0, 0, 0.5);
}

.video-caption h3 {
  margin: 0.5rem 0;
  font-size: 1.1rem;
  color: var(--text);
}

.video-caption p {
  margin: 0 0 0.75rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.video-secondary {
  margin: 1.25rem 0 0;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.video-secondary a {
  font-weight: 600;
}

@media (max-width: 720px) {
  .video-featured {
    grid-template-columns: 1fr;
  }
}

/* Demos */
.demos {
  padding: 3rem 1.25rem;
  border-bottom: 1px solid var(--border);
}

.section-inner {
  max-width: 960px;
  margin: 0 auto;
}

.demos h2 {
  margin: 0 0 1.25rem;
  font-size: 1.35rem;
}

.demo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.demo-card {
  display: block;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem 1.35rem;
  color: inherit;
  transition: border-color 0.15s, transform 0.15s;
}

.demo-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  color: inherit;
}

.demo-tag {
  display: inline-block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent);
  background: rgba(59, 157, 221, 0.12);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  margin-bottom: 0.65rem;
}

.demo-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.1rem;
  color: var(--text);
}

.demo-card p {
  margin: 0 0 1rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.demo-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
}

/* Docs layout */
.docs-layout {
  display: flex;
  max-width: 1200px;
  margin: 0 auto;
  min-height: 60vh;
}

.sidebar {
  position: sticky;
  top: var(--header-height);
  width: var(--sidebar-width);
  flex-shrink: 0;
  height: calc(100vh - var(--header-height));
  overflow-y: auto;
  padding: 1.5rem 0 2rem 1.25rem;
  border-right: 1px solid var(--border);
}

.sidebar-title {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin: 0 0 0.75rem;
  padding-right: 1rem;
}

#sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  padding-right: 1rem;
}

#sidebar-nav a {
  display: block;
  font-size: 0.85rem;
  color: var(--text-muted);
  padding: 0.35rem 0.5rem;
  border-radius: 4px;
  border-left: 2px solid transparent;
  line-height: 1.35;
}

#sidebar-nav a:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.04);
}

#sidebar-nav a.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: rgba(59, 157, 221, 0.08);
}

#sidebar-nav a.nav-h3 {
  padding-left: 1rem;
  font-size: 0.8rem;
}

.sidebar-loading {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0;
}

.docs-main {
  flex: 1;
  min-width: 0;
  padding: 2rem 2rem 4rem;
}

.docs-loading {
  color: var(--text-muted);
}

/* Markdown body */
.markdown-body h1 {
  display: none;
}

.markdown-body h2 {
  font-size: 1.45rem;
  margin: 2.5rem 0 1rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border);
}

.markdown-body h2:first-child {
  margin-top: 0;
  border-top: none;
  padding-top: 0;
}

.markdown-body h3 {
  font-size: 1.1rem;
  margin: 1.75rem 0 0.75rem;
  color: var(--text);
}

.markdown-body h4 {
  font-size: 1rem;
  margin: 1.25rem 0 0.5rem;
}

.markdown-body p,
.markdown-body li {
  color: #c8d2e0;
}

.markdown-body strong {
  color: var(--text);
}

.markdown-body ul,
.markdown-body ol {
  padding-left: 1.4rem;
}

.markdown-body li {
  margin-bottom: 0.35rem;
}

.markdown-body code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: rgba(255, 255, 255, 0.08);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.markdown-body pre {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.1rem;
  overflow-x: auto;
  margin: 1rem 0;
}

.markdown-body pre code {
  background: none;
  padding: 0;
  font-size: 0.82rem;
  line-height: 1.5;
}

.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
}

.markdown-body th,
.markdown-body td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.75rem;
  text-align: left;
}

.markdown-body th {
  background: var(--bg-elevated);
  color: var(--text);
}

.markdown-body img {
  max-width: 100%;
}

.markdown-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2rem 0;
}

.markdown-body blockquote {
  margin: 1rem 0;
  padding-left: 1rem;
  border-left: 3px solid var(--accent);
  color: var(--text-muted);
}

.markdown-body a {
  word-break: break-word;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 1.25rem;
  text-align: center;
}

.site-footer p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.site-footer a {
  color: var(--text-muted);
}

.site-footer a:hover {
  color: var(--accent);
}

/* Mobile */
@media (max-width: 860px) {
  .sidebar-toggle {
    display: block;
  }

  .header-links {
    display: none;
  }

  .docs-layout {
    flex-direction: column;
  }

  .sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    z-index: 90;
    width: min(var(--sidebar-width), 85vw);
    transform: translateX(-100%);
    transition: transform 0.2s;
    background: var(--bg);
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.4);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .docs-main {
    padding: 1.5rem 1.25rem 3rem;
  }
}