:root {
  --docs-bg: #f8fafc;
  --docs-ink: #0f172a;
  --docs-muted: #475569;
  --docs-surface: #ffffff;
  --docs-accent: #1e40af;
  --docs-accent-ink: #ffffff;
  --docs-border: #e2e8f0;
  --docs-band: #eff6ff;
  --docs-shadow: 0 8px 20px rgba(15, 23, 42, 0.06);
  --docs-code-bg: #1e293b;
  --docs-sidebar-w: 260px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color: var(--docs-ink);
  background: var(--docs-bg);
  line-height: 1.6;
}

a { color: var(--docs-accent); }
code, pre { font-family: "SF Mono", "Fira Code", "Consolas", monospace; }

/* ─── Utilities ─── */
.container { width: min(1100px, 100% - 2rem); margin: 0 auto; }
.surface {
  background: var(--docs-surface);
  border: 1px solid var(--docs-border);
  border-radius: 12px;
  padding: 1rem;
  box-shadow: var(--docs-shadow);
}
.stack-sm > * + * { margin-top: 0.45rem; }
.stack-md > * + * { margin-top: 0.8rem; }

/* ─── Skip link ─── */
.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: #fff;
  padding: 0.5rem 0.7rem;
  z-index: 100;
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; }

/* ─── Header ─── */
.docs-header {
  position: sticky;
  top: 0;
  z-index: 30;
  border-bottom: 1px solid var(--docs-border);
  background: rgba(248, 250, 252, 0.92);
  backdrop-filter: blur(8px);
}

.docs-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem 0;
}

.docs-brand {
  font-weight: 800;
  letter-spacing: 0.06em;
  text-decoration: none;
  color: var(--docs-ink);
}

.docs-header nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.docs-header nav a {
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 0.3rem 0.7rem;
  font-size: 0.9rem;
}

.docs-header nav a[aria-current="page"] {
  border-color: var(--docs-border);
  background: var(--docs-surface);
}

/* ─── Language switch ─── */
.docs-lang {
  display: flex;
  gap: 0.3rem;
  align-items: center;
  font-size: 0.85rem;
}

.docs-lang button {
  border: 1px solid var(--docs-border);
  border-radius: 999px;
  padding: 0.3rem 0.7rem;
  background: transparent;
  color: var(--docs-muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.82rem;
}

.docs-lang button.is-active {
  background: var(--docs-accent);
  color: var(--docs-accent-ink);
  border-color: var(--docs-accent);
}

/* ─── Bilingual toggle ─── */
[data-lang="en"] [data-vi] { display: none !important; }
[data-lang="vi"] [data-en] { display: none !important; }

/* ─── Layout: sidebar + main ─── */
.docs-layout {
  display: flex;
  min-height: calc(100vh - 56px);
}

/* ─── Sidebar ─── */
.docs-sidebar {
  width: var(--docs-sidebar-w);
  flex-shrink: 0;
  border-right: 1px solid var(--docs-border);
  background: var(--docs-surface);
  padding: 1.2rem 0;
  overflow-y: auto;
  position: sticky;
  top: 56px;
  height: calc(100vh - 56px);
}

.docs-nav {
  list-style: none;
  margin: 0;
  padding: 0;
}

.docs-nav li { margin: 0; }

.docs-nav a {
  display: block;
  text-decoration: none;
  padding: 0.35rem 1.2rem;
  color: var(--docs-muted);
  font-size: 0.9rem;
  border-left: 3px solid transparent;
  transition: background 0.15s, color 0.15s;
}

.docs-nav a:hover { background: var(--docs-band); color: var(--docs-ink); }

.docs-nav a.is-active {
  color: var(--docs-accent);
  border-left-color: var(--docs-accent);
  background: var(--docs-band);
  font-weight: 600;
}

/* nested nav */
.docs-nav .docs-nav { padding-left: 0.8rem; }
.docs-nav .docs-nav a { font-size: 0.85rem; padding-block: 0.25rem; }

.docs-menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--docs-border);
  border-radius: 8px;
  padding: 0.4rem 0.6rem;
  cursor: pointer;
  font-size: 1.1rem;
}

/* ─── Main content ─── */
.docs-main {
  flex: 1;
  min-width: 0;
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* ─── Table of contents ─── */
.docs-toc {
  position: sticky;
  top: 72px;
  font-size: 0.82rem;
  padding: 0.8rem 0;
  border-left: 2px solid var(--docs-border);
  margin-left: 1rem;
  padding-left: 1rem;
}

.docs-toc ul { list-style: none; margin: 0; padding: 0; }
.docs-toc li + li { margin-top: 0.35rem; }
.docs-toc a { text-decoration: none; color: var(--docs-muted); }
.docs-toc a:hover { color: var(--docs-accent); }

/* ─── Hero ─── */
.docs-hero {
  padding: 3rem 0;
  text-align: center;
  background: var(--docs-band);
  border-bottom: 1px solid var(--docs-border);
}

.docs-hero h1 {
  margin: 0 0 0.6rem;
  font-size: clamp(1.6rem, 2.7vw, 2.5rem);
  line-height: 1.15;
}

.docs-hero p { color: var(--docs-muted); max-width: 560px; margin: 0 auto; }

/* ─── Grid ─── */
.docs-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.docs-cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

/* ─── Cards ─── */
.docs-card {
  background: var(--docs-surface);
  border: 1px solid var(--docs-border);
  border-radius: 12px;
  padding: 1.1rem;
  box-shadow: var(--docs-shadow);
  transition: box-shadow 0.2s, transform 0.2s;
}

.docs-card:hover {
  box-shadow: 0 12px 28px rgba(15, 23, 42, 0.1);
  transform: translateY(-2px);
}

.docs-card h3 { margin: 0 0 0.4rem; font-size: 1.05rem; }
.docs-card p { margin: 0; color: var(--docs-muted); font-size: 0.9rem; }
.docs-card-icon { display: inline-block; font-size: 1.4rem; margin-bottom: 0.5rem; }

/* ─── Table ─── */
.docs-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.docs-table th,
.docs-table td {
  border: 1px solid var(--docs-border);
  padding: 0.55rem 0.7rem;
  text-align: left;
}

.docs-table th { background: var(--docs-band); font-weight: 600; }

/* ─── Code blocks ─── */
.docs-code {
  background: var(--docs-code-bg);
  color: #e2e8f0;
  border-radius: 10px;
  padding: 0.9rem 1rem;
  overflow-x: auto;
  font-size: 0.88rem;
  line-height: 1.5;
}

.docs-code pre { margin: 0; white-space: pre-wrap; }

.docs-copy-btn {
  position: absolute;
  top: 0.35rem;
  right: 0.35rem;
  border: 1px solid rgba(226, 232, 240, 0.25);
  border-radius: 999px;
  padding: 0.2rem 0.55rem;
  background: rgba(15, 23, 42, 0.75);
  color: #e2e8f0;
  cursor: pointer;
  font: inherit;
  font-size: 0.72rem;
}

/* ─── Badges ─── */
.docs-badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  background: var(--docs-band);
  color: var(--docs-accent);
  border: 1px solid var(--docs-border);
}

.docs-badge.is-live { background: #ecfdf5; color: #047857; border-color: #a7f3d0; }
.docs-badge.is-planned { background: #fef3c7; color: #92400e; border-color: #fde68a; }

/* ─── Footer ─── */
.docs-footer {
  border-top: 1px solid var(--docs-border);
  padding: 1.6rem 0 2.4rem;
  background: var(--docs-surface);
  color: var(--docs-muted);
  font-size: 0.85rem;
  text-align: center;
}

/* ─── Focus visible ─── */
:focus-visible {
  outline: 3px solid var(--docs-accent);
  outline-offset: 2px;
  border-radius: 4px;
}

:focus:not(:focus-visible) { outline: none; }

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

/* ─── Mobile ─── */
@media (max-width: 860px) {
  .docs-grid,
  .docs-cards { grid-template-columns: 1fr; }

  .docs-menu-toggle { display: block; }

  .docs-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    z-index: 40;
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    box-shadow: 4px 0 20px rgba(0, 0, 0, 0.15);
  }

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

  .docs-main { padding: 1.2rem 1rem; }

  .docs-header .container {
    flex-wrap: wrap;
  }

  .docs-toc { display: none; }
}

@media (max-width: 600px) {
  .docs-grid,
  .docs-cards { grid-template-columns: 1fr; }
}

/* ─── Print ─── */
@media print {
  .docs-sidebar,
  .docs-header nav,
  .docs-lang,
  .docs-menu-toggle,
  .docs-footer,
  .docs-toc { display: none; }

  .docs-layout { display: block; }
  .docs-main { max-width: 100%; padding: 0; }
}