/* WebGPU OS Docs — zero-build viewer theme (dark slate + cyan, matches OS shell).
 * Part of the WebGPU OS stack.
 * Author: Jake Wehmeier (BTSpaniel) — https://github.com/BTSpaniel
 */
:root {
  --bg: #0f172a;
  --bg-elev: #111c33;
  --bg-elev-2: #16233f;
  --border: #243149;
  --text: #e2e8f0;
  --text-dim: #94a3b8;
  --text-faint: #64748b;
  --accent: #38bdf8;
  --accent-2: #22d3ee;
  --accent-soft: rgba(56, 189, 248, 0.14);
  --warn: #fbbf24;
  --danger: #f87171;
  --ok: #34d399;
  --code-bg: #0b1220;
  --radius: 10px;
  --sidebar-w: 290px;
  --toc-w: 240px;
  --topbar-h: 56px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: "SFMono-Regular", "JetBrains Mono", Consolas, "Liberation Mono", Menlo, monospace;
  --scroll-thumb: #2c3d5c;
  --scroll-thumb-hover: #3d567f;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 15.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 100;
  background: var(--accent); color: #00111c; padding: 8px 14px; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------- Topbar ---------- */
.topbar {
  position: fixed; top: 0; left: 0; right: 0; height: var(--topbar-h);
  display: flex; align-items: center; gap: 14px; padding: 0 16px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border); z-index: 40;
}
.icon-btn {
  background: transparent; border: 1px solid var(--border); color: var(--text);
  width: 38px; height: 38px; border-radius: 8px; cursor: pointer; font-size: 18px;
}
.icon-btn:hover { background: var(--bg-elev-2); }
.brand { display: flex; align-items: center; gap: 8px; font-weight: 700; color: var(--text); }
.brand:hover { text-decoration: none; }
.brand-mark {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #00111c; padding: 4px 8px; border-radius: 7px; font-size: 13px; letter-spacing: 0.5px;
}
.brand-text { color: var(--text); font-size: 15px; }

.search-wrap { position: relative; margin-left: auto; width: min(420px, 42vw); }
#search-input {
  width: 100%; background: var(--code-bg); border: 1px solid var(--border);
  color: var(--text); border-radius: 9px; padding: 9px 12px; font-size: 14px; outline: none;
}
#search-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.search-results {
  position: absolute; top: 110%; left: 0; right: 0; margin: 0; padding: 6px; list-style: none;
  background: var(--bg-elev-2); border: 1px solid var(--border); border-radius: 10px;
  max-height: 60vh; overflow-y: auto; z-index: 60; box-shadow: 0 18px 40px rgba(0,0,0,0.5);
}
.search-results li { padding: 0; }
.search-results a { display: block; padding: 9px 11px; border-radius: 8px; color: var(--text); }
.search-results a:hover, .search-results a.active { background: var(--accent-soft); text-decoration: none; }
.search-results .sr-title { font-weight: 600; }
.search-results .sr-crumb { display: block; font-size: 12px; color: var(--text-faint); }
.search-results .sr-snippet { display: block; font-size: 12.5px; color: var(--text-dim); margin-top: 2px; }
.search-results mark { background: rgba(56,189,248,0.28); color: var(--text); border-radius: 3px; }
.search-empty { padding: 12px; color: var(--text-faint); font-size: 13px; }

.version-badge {
  font-size: 12px; color: var(--text-dim); border: 1px solid var(--border);
  padding: 4px 9px; border-radius: 20px; white-space: nowrap;
}

/* ---------- Layout ---------- */
.layout { display: flex; padding-top: var(--topbar-h); min-height: 100vh; }

.sidebar {
  width: var(--sidebar-w); flex: 0 0 var(--sidebar-w);
  position: sticky; top: var(--topbar-h); align-self: flex-start;
  height: calc(100vh - var(--topbar-h)); overflow-y: auto;
  border-right: 1px solid var(--border); background: var(--bg);
  padding: 0 8px 60px;
}
.sidebar.collapsed { display: none; }

.nav-section { margin-bottom: 8px; }
.nav-section-title {
  display: flex; align-items: center; gap: 8px; width: 100%;
  background: transparent; border: 0; color: var(--text-dim); cursor: pointer;
  font-size: 12px; font-weight: 700; letter-spacing: 0.8px; text-transform: uppercase;
  padding: 8px 10px; border-radius: 8px; text-align: left;
}
.nav-section-title:hover { background: var(--bg-elev); color: var(--text); }
.nav-section-title .chevron { margin-left: auto; transition: transform 0.15s; color: var(--text-faint); }
.nav-section.collapsed .chevron { transform: rotate(-90deg); }
.nav-section.collapsed .nav-items { display: none; }
.nav-items { list-style: none; margin: 2px 0 6px; padding: 0; }
.nav-items li { margin: 1px 0; }
.nav-items a {
  display: block; padding: 6px 12px 6px 22px; border-radius: 8px; color: var(--text-dim);
  font-size: 14px; border-left: 2px solid transparent;
}
.nav-items a:hover { background: var(--bg-elev); color: var(--text); text-decoration: none; }
.nav-items a.active {
  background: var(--accent-soft); color: var(--accent); border-left-color: var(--accent); font-weight: 600;
}
.nav-group-title {
  padding: 8px 12px 4px 16px; font-size: 11px; font-weight: 700; color: var(--text-faint);
  text-transform: uppercase; letter-spacing: 0.6px;
}

/* ---------- Main content ---------- */
.main { flex: 1 1 auto; min-width: 0; padding: 34px 46px 80px; max-width: 920px; margin: 0 auto; }
.doc-content { outline: none; }
.loading { color: var(--text-faint); }

.doc-content h1, .doc-content h2, .doc-content h3, .doc-content h4 { line-height: 1.25; scroll-margin-top: calc(var(--topbar-h) + 14px); }
.doc-content h1 { font-size: 2.1rem; margin: 0 0 0.6em; padding-bottom: 0.3em; border-bottom: 1px solid var(--border); }
.doc-content h2 { font-size: 1.5rem; margin: 1.8em 0 0.6em; padding-bottom: 0.25em; border-bottom: 1px solid var(--border); }
.doc-content h3 { font-size: 1.2rem; margin: 1.5em 0 0.5em; color: #cbd5e1; }
.doc-content h4 { font-size: 1.02rem; margin: 1.2em 0 0.4em; color: var(--text-dim); }
.doc-content p { margin: 0.7em 0; }
.doc-content ul, .doc-content ol { margin: 0.6em 0; padding-left: 1.5em; }
.doc-content li { margin: 0.25em 0; }
.doc-content blockquote {
  margin: 1em 0; padding: 2px 16px; border-left: 4px solid var(--accent);
  background: var(--bg-elev); color: var(--text-dim); border-radius: 0 8px 8px 0;
}
.doc-content img { max-width: 100%; border-radius: 8px; }
.doc-content hr { border: 0; border-top: 1px solid var(--border); margin: 2em 0; }

/* heading anchor */
.heading-anchor { opacity: 0; margin-left: 8px; font-size: 0.8em; color: var(--text-faint); }
h1:hover .heading-anchor, h2:hover .heading-anchor, h3:hover .heading-anchor, h4:hover .heading-anchor { opacity: 1; }

/* code */
.doc-content code {
  font-family: var(--mono); font-size: 0.88em; background: var(--code-bg);
  border: 1px solid var(--border); border-radius: 5px; padding: 1px 6px;
}
.doc-content pre {
  position: relative; background: var(--code-bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px 16px; overflow-x: auto; margin: 1em 0;
}
.doc-content pre code { background: transparent; border: 0; padding: 0; font-size: 13.5px; line-height: 1.55; }
.copy-btn {
  position: absolute; top: 8px; right: 8px; background: var(--bg-elev-2); border: 1px solid var(--border);
  color: var(--text-dim); border-radius: 6px; padding: 3px 9px; font-size: 12px; cursor: pointer; opacity: 0;
  transition: opacity 0.12s;
}
.doc-content pre:hover .copy-btn { opacity: 1; }
.copy-btn:hover { color: var(--text); border-color: var(--accent); }
.copy-btn.copied { color: var(--ok); border-color: var(--ok); }

/* tables */
.doc-content table { border-collapse: collapse; width: 100%; margin: 1em 0; font-size: 14px; display: block; overflow-x: auto; }
.doc-content th, .doc-content td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
.doc-content thead th { background: var(--bg-elev); }
.doc-content tbody tr:nth-child(even) { background: rgba(255,255,255,0.02); }

/* mermaid */
.mermaid { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px; margin: 1em 0; text-align: center; }

/* callouts via blockquote markers */
.callout { border-radius: 8px; padding: 10px 16px; margin: 1em 0; border-left: 4px solid var(--accent); background: var(--bg-elev); }
.callout-warn { border-left-color: var(--warn); }
.callout-danger { border-left-color: var(--danger); }
.callout-ok { border-left-color: var(--ok); }

/* page nav */
.page-nav { display: flex; justify-content: space-between; gap: 12px; margin-top: 40px; }
.page-nav-link { flex: 1; border: 1px solid var(--border); border-radius: 10px; padding: 12px 16px; color: var(--text); background: var(--bg-elev); }
.page-nav-link:hover { border-color: var(--accent); text-decoration: none; }
.page-nav-next { text-align: right; }

.doc-footer {
  margin-top: 30px; padding-top: 16px; border-top: 1px solid var(--border);
  color: var(--text-faint); font-size: 12.5px;
  display: flex; flex-wrap: wrap; gap: 8px 18px; align-items: center; justify-content: space-between;
}
.footer-credit { margin-left: auto; }
.footer-credit a { color: var(--text-dim); font-weight: 600; }
.footer-credit a:hover { color: var(--accent); }

/* ---------- TOC ---------- */
.toc {
  width: var(--toc-w); flex: 0 0 var(--toc-w); position: sticky; top: var(--topbar-h);
  align-self: flex-start; height: calc(100vh - var(--topbar-h)); overflow-y: auto;
  padding: 34px 18px; border-left: 1px solid var(--border);
}
.toc-title { font-size: 12px; text-transform: uppercase; letter-spacing: 0.7px; color: var(--text-faint); margin: 0 0 10px; }
.toc-list { list-style: none; margin: 0; padding: 0; font-size: 13.5px; border-left: 1px solid var(--border); }
.toc-list li a { display: block; padding: 4px 0 4px 12px; color: var(--text-dim); margin-left: -1px; border-left: 2px solid transparent; }
.toc-list li a:hover { color: var(--text); text-decoration: none; }
.toc-list li a.active { color: var(--accent); border-left-color: var(--accent); }
.toc-list .toc-h3 a { padding-left: 24px; font-size: 13px; }

/* ---------- Responsive ---------- */
.nav-backdrop {
  position: fixed; inset: var(--topbar-h) 0 0 0; z-index: 55;
  background: rgba(2, 6, 18, 0.55);
}
@media (min-width: 901px) { .nav-backdrop { display: none !important; } }
@media (max-width: 1200px) { .toc { display: none; } }
@media (max-width: 900px) {
  .sidebar {
    position: fixed; top: var(--topbar-h); left: 0; z-index: 60;
    width: min(86vw, var(--sidebar-w));
    box-shadow: 6px 0 30px rgba(0,0,0,0.5);
  }
  .sidebar.collapsed { display: none; }
  .main { padding: 24px 18px 60px; width: 100%; }
  .search-wrap { width: 42vw; }
}

@media print {
  .topbar, .sidebar, .toc, .page-nav, .copy-btn, .read-progress, .back-to-top, .breadcrumbs { display: none !important; }
  .main { max-width: 100%; padding: 0; }
}

/* ====================================================================== */
/* QoL enhancements: scrollbars, collapsible reference tree, filter, etc.  */
/* ====================================================================== */

/* ---------- Custom scrollbars ---------- */
* { scrollbar-width: thin; scrollbar-color: var(--scroll-thumb) transparent; }
::-webkit-scrollbar { width: 12px; height: 12px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--scroll-thumb); border-radius: 10px;
  border: 3px solid var(--bg); background-clip: padding-box;
}
::-webkit-scrollbar-thumb:hover { background: var(--scroll-thumb-hover); }
::-webkit-scrollbar-corner { background: transparent; }
.doc-content pre::-webkit-scrollbar { height: 10px; }
.doc-content pre::-webkit-scrollbar-thumb { border-color: var(--code-bg); }
.search-results::-webkit-scrollbar-thumb,
.sidebar::-webkit-scrollbar-thumb { border-color: var(--bg); }

/* ---------- Sidebar tools (filter + collapse-all) ---------- */
.sidebar-tools {
  position: sticky; top: 0; z-index: 6; display: flex; gap: 6px;
  padding: 12px 4px 10px; margin: 0 -8px 0; padding-left: 12px; padding-right: 12px;
  background: var(--bg); border-bottom: 1px solid var(--border);
}
#nav-filter {
  flex: 1; min-width: 0; background: var(--code-bg); border: 1px solid var(--border);
  color: var(--text); border-radius: 8px; padding: 7px 10px; font-size: 13px; outline: none;
}
#nav-filter:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.nav-tool-btn {
  flex: 0 0 auto; background: transparent; border: 1px solid var(--border);
  color: var(--text-dim); border-radius: 8px; width: 34px; cursor: pointer; font-size: 14px;
}
.nav-tool-btn:hover { color: var(--text); border-color: var(--accent); }
.nav-tree { padding-top: 10px; }

/* ---------- Collapsible reference folders ---------- */
.nav-folder-title {
  display: flex; align-items: center; gap: 6px; width: 100%;
  background: transparent; border: 0; color: var(--text-dim); cursor: pointer;
  font-size: 13px; padding: 5px 8px; border-radius: 7px; text-align: left;
  transition: background .12s, color .12s;
}
.nav-folder-title:hover { background: var(--bg-elev); color: var(--text); }
.nav-folder-title .fchev {
  flex: 0 0 auto; width: 11px; font-size: 10px; color: var(--text-faint);
  transition: transform .15s; text-align: center;
}
.nav-folder-title .ficon { flex: 0 0 auto; color: var(--text-faint); font-size: 12px; }
.nav-folder-title .fname { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.nav-folder-title .fcount {
  margin-left: auto; flex: 0 0 auto; font-size: 10.5px; color: var(--text-faint);
  background: var(--bg-elev-2); border-radius: 10px; padding: 1px 7px;
}
.nav-folder.collapsed > .nav-folder-items { display: none; }
.nav-folder.collapsed > .nav-folder-title .fchev { transform: rotate(-90deg); }
.nav-folder-items { list-style: none; margin: 0; padding: 0; }
.nav-folder-items a {
  display: block; padding: 5px 12px 5px 22px; border-radius: 7px; color: var(--text-dim);
  font-size: 13px; border-left: 2px solid transparent;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  transition: background .12s, color .12s;
}
.nav-folder-items a:hover { background: var(--bg-elev); color: var(--text); text-decoration: none; }
.nav-folder-items a.active {
  background: var(--accent-soft); color: var(--accent); border-left-color: var(--accent); font-weight: 600;
}

/* ---------- Sidebar filter results ---------- */
.nav-filter-results { list-style: none; margin: 4px 0; padding: 0; }
.nav-filter-results .nfr-section {
  font-size: 10.5px; text-transform: uppercase; letter-spacing: .6px;
  color: var(--text-faint); padding: 10px 10px 3px;
}
.nav-filter-results a {
  display: block; padding: 5px 10px; border-radius: 7px; color: var(--text-dim);
  font-size: 13px; border-left: 2px solid transparent;
}
.nav-filter-results a:hover { background: var(--bg-elev); color: var(--text); text-decoration: none; }
.nav-filter-results a.active { background: var(--accent-soft); color: var(--accent); border-left-color: var(--accent); }
.nav-filter-results .nfr-crumb { display: block; font-size: 11px; color: var(--text-faint); }
.nav-filter-more, .nav-empty { color: var(--text-faint); font-size: 12.5px; padding: 8px 10px; }
mark.nav-hl { background: rgba(56,189,248,.28); color: var(--text); border-radius: 3px; padding: 0 1px; }

/* ---------- Breadcrumbs ---------- */
.breadcrumbs { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; font-size: 12.5px; color: var(--text-faint); margin-bottom: 18px; }
.breadcrumbs:empty { display: none; }
.breadcrumbs a { color: var(--text-dim); }
.breadcrumbs a:hover { color: var(--accent); }
.breadcrumbs .sep { opacity: .55; }
.breadcrumbs .crumb-current { color: var(--text-dim); }

/* ---------- Reading progress bar ---------- */
.read-progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0; z-index: 60;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width .1s linear; pointer-events: none;
}

/* ---------- Back to top ---------- */
.back-to-top {
  position: fixed; right: 22px; bottom: 22px; z-index: 45;
  width: 42px; height: 42px; border-radius: 50%; border: 1px solid var(--border);
  background: var(--bg-elev-2); color: var(--text); font-size: 18px; cursor: pointer;
  box-shadow: 0 6px 20px rgba(0,0,0,.45); opacity: 0; transform: translateY(8px);
  transition: opacity .18s, transform .18s, border-color .18s, color .18s;
}
.back-to-top[hidden] { display: none; }
.back-to-top.show { opacity: 1; transform: translateY(0); }
.back-to-top:not(.show) { pointer-events: none; }
.back-to-top:hover { border-color: var(--accent); color: var(--accent); }
@media (max-width: 1200px) { .back-to-top { right: 16px; bottom: 16px; } }

/* ---------- Page subtitle (from frontmatter description) ---------- */
.page-subtitle {
  margin: -6px 0 20px; color: var(--text-dim); font-size: 1.05rem; line-height: 1.5;
  border-left: 3px solid var(--border); padding-left: 12px;
}

/* ---------- Reduced motion (accessibility) ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition: none !important;
    animation: none !important;
    scroll-behavior: auto !important;
  }
}