/* ---------- design tokens ---------- */
:root {
  --bg: #ffffff;
  --bg-2: #f6f8fa;
  --bg-3: #eef1f5;
  --fg: #1f2328;
  --fg-2: #59636e;
  --fg-3: #818b98;
  --border: #d8dee4;
  --accent: #0969da;
  --accent-2: #8250df;
  --code-bg: #f6f8fa;
  --code-fg: #1f2328;
  --pre-bg: #0d1117;
  --pre-fg: #e6edf3;
  --note: #0969da; --tip: #1a7f37; --important: #8250df; --warning: #9a6700; --caution: #cf222e;
  --shadow: 0 1px 2px rgba(0,0,0,.06), 0 8px 24px rgba(0,0,0,.06);
  --radius: 10px;
  --sidebar-w: 290px;
  --rightbar-w: 240px;
  --topbar-h: 56px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", Inter, "Segoe UI", Helvetica, Arial, sans-serif;
  --mono: "SF Mono", ui-monospace, "JetBrains Mono", Menlo, Consolas, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) { color-scheme: dark;
    --bg: #0d1117; --bg-2: #161b22; --bg-3: #1c2129; --fg: #e6edf3; --fg-2: #9198a1; --fg-3: #6e7681;
    --border: #30363d; --accent: #58a6ff; --accent-2: #bc8cff; --code-bg: #1c2129; --code-fg: #e6edf3;
    --pre-bg: #0a0d12; --pre-fg: #e6edf3;
    --note: #58a6ff; --tip: #3fb950; --important: #bc8cff; --warning: #d29922; --caution: #f85149;
    --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.4); }
}
:root[data-theme="dark"] { color-scheme: dark;
  --bg: #0d1117; --bg-2: #161b22; --bg-3: #1c2129; --fg: #e6edf3; --fg-2: #9198a1; --fg-3: #6e7681;
  --border: #30363d; --accent: #58a6ff; --accent-2: #bc8cff; --code-bg: #1c2129; --code-fg: #e6edf3;
  --pre-bg: #0a0d12; --pre-fg: #e6edf3;
  --note: #58a6ff; --tip: #3fb950; --important: #bc8cff; --warning: #d29922; --caution: #f85149;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.4); }

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--topbar-h) + 16px); -webkit-text-size-adjust: 100%; }
body { margin: 0; font: 16px/1.65 var(--font); color: var(--fg); background: var(--bg); }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; }
kbd { font: 0.85em var(--mono); background: var(--bg-2); border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 5px; padding: 1px 6px; color: var(--fg); white-space: nowrap; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--accent); color: #fff; padding: 8px 12px; border-radius: 6px; z-index: 100; }
.skip:focus { left: 8px; }

/* ---------- top bar ---------- */
.topbar { position: sticky; top: 0; z-index: 50; height: var(--topbar-h); display: flex; align-items: center; gap: 12px; padding: 0 16px; background: color-mix(in srgb, var(--bg) 85%, transparent); backdrop-filter: saturate(180%) blur(14px); -webkit-backdrop-filter: saturate(180%) blur(14px); border-bottom: 1px solid var(--border); }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--fg); letter-spacing: -.01em; font-size: 17px; }
.brand:hover { text-decoration: none; }
.brand img { border-radius: 7px; }
.topbar-right { margin-left: auto; display: flex; align-items: center; gap: 8px; }
.search-btn { display: flex; align-items: center; gap: 8px; height: 36px; padding: 0 12px; border: 1px solid var(--border); background: var(--bg-2); color: var(--fg-2); border-radius: 8px; cursor: pointer; font: inherit; font-size: 14px; }
.search-btn:hover { border-color: var(--fg-3); color: var(--fg); }
.search-btn kbd { font-size: 12px; }
.theme-btn, .gh { display: inline-flex; align-items: center; justify-content: center; width: 36px; height: 36px; border-radius: 8px; border: 1px solid var(--border); background: var(--bg-2); color: var(--fg-2); cursor: pointer; font-size: 18px; }
.theme-btn:hover, .gh:hover { color: var(--fg); border-color: var(--fg-3); text-decoration: none; }
.menu-btn { display: none; width: 36px; height: 36px; border: 1px solid var(--border); background: var(--bg-2); border-radius: 8px; cursor: pointer; flex-direction: column; justify-content: center; gap: 4px; align-items: center; }
.menu-btn span { display: block; width: 16px; height: 2px; background: var(--fg); border-radius: 1px; }

/* ---------- layout ---------- */
.layout { display: grid; grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--rightbar-w); max-width: 1440px; margin: 0 auto; }
.sidebar { position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h)); overflow-y: auto; padding: 20px 12px 40px 16px; border-right: 1px solid var(--border); scrollbar-width: thin; }
.sidebar nav ul { list-style: none; margin: 0 0 6px; padding: 0; }
.sidebar nav li a { display: flex; gap: 8px; padding: 6px 10px; border-radius: 7px; color: var(--fg-2); font-size: 14px; line-height: 1.4; }
.sidebar nav li a:hover { background: var(--bg-2); color: var(--fg); text-decoration: none; }
.sidebar nav li.active a { background: color-mix(in srgb, var(--accent) 12%, transparent); color: var(--accent); font-weight: 600; }
.nav-num { color: var(--fg-3); font-variant-numeric: tabular-nums; min-width: 1.6em; font-size: 12px; padding-top: 2px; }
.sidebar nav li.active .nav-num { color: var(--accent); }
.nav-part { margin: 18px 10px 6px; font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--fg-3); font-weight: 700; }
.nav-home { display: block; padding: 8px 10px; border-radius: 7px; font-weight: 600; font-size: 14px; color: var(--fg); }
.nav-home:hover { background: var(--bg-2); text-decoration: none; }
.nav-home.active { background: color-mix(in srgb, var(--accent) 12%, transparent); color: var(--accent); }
.content { min-width: 0; padding: 32px 48px 64px; }
.rightbar { position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h)); overflow-y: auto; padding: 28px 16px 40px 8px; font-size: 13px; scrollbar-width: thin; }
.toc-title { margin: 0 0 8px; font-size: 11px; text-transform: uppercase; letter-spacing: .08em; color: var(--fg-3); font-weight: 700; }
.toc ul { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--border); }
.toc li a { display: block; padding: 4px 12px; color: var(--fg-2); border-left: 2px solid transparent; margin-left: -1px; line-height: 1.4; }
.toc li.lvl3 a { padding-left: 24px; font-size: 12.5px; }
.toc li a:hover { color: var(--fg); text-decoration: none; }
.toc li a.active { color: var(--accent); border-left-color: var(--accent); }

/* ---------- prose ---------- */
.prose { max-width: 820px; }
.prose h1 { font-size: 2.35rem; line-height: 1.15; letter-spacing: -.02em; margin: 0 0 .6em; font-weight: 800; }
.prose h2 { font-size: 1.6rem; margin: 2.2em 0 .7em; padding-top: .4em; border-top: 1px solid var(--border); letter-spacing: -.01em; font-weight: 700; }
.prose h3 { font-size: 1.22rem; margin: 1.8em 0 .5em; font-weight: 700; }
.prose h4 { font-size: 1.02rem; margin: 1.4em 0 .4em; font-weight: 700; text-transform: uppercase; letter-spacing: .04em; color: var(--fg-2); }
.prose h5, .prose h6 { font-size: .95rem; margin: 1.2em 0 .3em; }
.anchor { margin-left: .4em; color: var(--fg-3); opacity: 0; font-weight: 400; }
h2:hover .anchor, h3:hover .anchor, h4:hover .anchor { opacity: 1; }
.prose p, .prose ul, .prose ol { margin: 0 0 1.05em; }
.prose li { margin: .3em 0; }
.prose li > ul, .prose li > ol { margin: .3em 0 .3em; }
.prose ul { padding-left: 1.5em; }
.prose ol { padding-left: 1.7em; }
.task-list { list-style: none; padding-left: .4em; }
.task-list li.task { display: flex; gap: 8px; align-items: flex-start; }
.task-list input { margin-top: .4em; }
.prose hr { border: 0; border-top: 1px solid var(--border); margin: 2.5em 0; }
.prose blockquote { margin: 1.2em 0; padding: .2em 1.2em; border-left: 4px solid var(--border); color: var(--fg-2); }
.prose strong { font-weight: 650; }
.prose code { font: .875em var(--mono); background: var(--code-bg); color: var(--code-fg); padding: .15em .4em; border-radius: 5px; border: 1px solid var(--border); }
.prose a code { color: inherit; }
.prose h1 code, .prose h2 code, .prose h3 code { font-size: .85em; }

/* code blocks */
.codeblock { position: relative; margin: 1.2em 0; border-radius: var(--radius); background: var(--pre-bg); border: 1px solid var(--border); overflow: hidden; }
.codeblock pre { margin: 0; padding: 16px 18px; overflow-x: auto; font: 13.5px/1.55 var(--mono); color: var(--pre-fg); tab-size: 4; }
.codeblock code { background: none; border: 0; padding: 0; color: inherit; font-size: inherit; }
.code-lang { position: absolute; top: 8px; right: 70px; font: 11px var(--mono); color: #8b949e; text-transform: lowercase; user-select: none; }
.codeblock .copy { position: absolute; top: 6px; right: 8px; font: 12px var(--font); color: #c9d1d9; background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.12); border-radius: 6px; padding: 3px 9px; cursor: pointer; opacity: 0; transition: opacity .15s; }
.codeblock:hover .copy, .codeblock .copy:focus { opacity: 1; }
.codeblock .copy:hover { background: rgba(255,255,255,.16); }
.codeblock .copy.done { color: #7ee787; border-color: #7ee787; }
/* tiny syntax colouring via JS-added spans */
.tok-c { color: #8b949e; font-style: italic; }
.tok-s { color: #a5d6ff; }
.tok-k { color: #ff7b72; }
.tok-f { color: #d2a8ff; }
.tok-v { color: #ffa657; }
.tok-p { color: #79c0ff; }
.tok-n { color: #79c0ff; }

/* tables */
.table-wrap { overflow-x: auto; margin: 1.2em 0; border: 1px solid var(--border); border-radius: var(--radius); }
.prose table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
.prose th, .prose td { padding: 9px 12px; border-bottom: 1px solid var(--border); vertical-align: top; text-align: left; }
.prose th { background: var(--bg-2); font-weight: 650; white-space: nowrap; }
.prose tr:last-child td { border-bottom: 0; }
.prose tbody tr:nth-child(even) { background: color-mix(in srgb, var(--bg-2) 55%, transparent); }

/* admonitions */
.admonition { margin: 1.3em 0; padding: 12px 16px 4px; border-left: 4px solid var(--note); border-radius: 8px; background: color-mix(in srgb, var(--note) 7%, var(--bg)); }
.admonition-title { font-weight: 700; margin: 0 0 6px !important; color: var(--note); display: flex; align-items: center; gap: 8px; font-size: 14px; text-transform: uppercase; letter-spacing: .04em; }
.admonition-title::before { content: "ⓘ"; font-size: 15px; }
.admonition.tip { border-color: var(--tip); background: color-mix(in srgb, var(--tip) 7%, var(--bg)); } .admonition.tip .admonition-title { color: var(--tip); } .admonition.tip .admonition-title::before { content: "💡"; }
.admonition.important { border-color: var(--important); background: color-mix(in srgb, var(--important) 7%, var(--bg)); } .admonition.important .admonition-title { color: var(--important); } .admonition.important .admonition-title::before { content: "❗"; }
.admonition.warning { border-color: var(--warning); background: color-mix(in srgb, var(--warning) 8%, var(--bg)); } .admonition.warning .admonition-title { color: var(--warning); } .admonition.warning .admonition-title::before { content: "⚠️"; }
.admonition.caution { border-color: var(--caution); background: color-mix(in srgb, var(--caution) 7%, var(--bg)); } .admonition.caution .admonition-title { color: var(--caution); } .admonition.caution .admonition-title::before { content: "🛑"; }
.admonition p:last-child { margin-bottom: .6em; }

details { margin: 1em 0; border: 1px solid var(--border); border-radius: 8px; padding: 0 14px; background: var(--bg-2); }
details summary { cursor: pointer; padding: 10px 0; font-weight: 600; }
details[open] summary { border-bottom: 1px solid var(--border); margin-bottom: 8px; }

/* landing cards */
.part-title { font-size: 1.15rem !important; margin: 2em 0 .8em !important; border-top: 0 !important; color: var(--fg-2); text-transform: uppercase; letter-spacing: .06em; font-weight: 700; }
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 12px; margin-bottom: 1.5em; }
.card { display: flex; flex-direction: column; gap: 4px; padding: 14px 16px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-2); color: var(--fg); transition: transform .12s, box-shadow .12s, border-color .12s; }
.card:hover { text-decoration: none; transform: translateY(-2px); box-shadow: var(--shadow); border-color: var(--accent); }
.card-num { font: 12px var(--mono); color: var(--accent); }
.card-title { font-weight: 650; line-height: 1.3; }
.card-desc { font-size: 13px; color: var(--fg-2); line-height: 1.45; }
.hero { padding: 8px 0 8px; }
.hero .lede { font-size: 1.2rem; color: var(--fg-2); max-width: 720px; }
.badges { display: flex; flex-wrap: wrap; gap: 8px; margin: 1em 0 1.5em; }
.badge { font-size: 12.5px; padding: 4px 10px; border-radius: 999px; background: var(--bg-3); color: var(--fg-2); border: 1px solid var(--border); }

/* pager & footer */
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; max-width: 820px; margin: 3em 0 1em; }
.pager-link { display: flex; flex-direction: column; padding: 14px 16px; border: 1px solid var(--border); border-radius: var(--radius); color: var(--fg); background: var(--bg-2); }
.pager-link:hover { text-decoration: none; border-color: var(--accent); }
.pager-link span { font-size: 12px; color: var(--fg-3); text-transform: uppercase; letter-spacing: .06em; }
.pager-link.next { text-align: right; align-items: flex-end; }
.page-footer { max-width: 820px; margin-top: 2em; padding-top: 1.2em; border-top: 1px solid var(--border); font-size: 13px; color: var(--fg-3); }

/* search modal */
.search-modal { position: fixed; inset: 0; background: rgba(0,0,0,.45); z-index: 100; display: flex; align-items: flex-start; justify-content: center; padding: 10vh 16px; backdrop-filter: blur(3px); }
.search-modal[hidden] { display: none; }
.search-panel { width: 100%; max-width: 680px; background: var(--bg); border: 1px solid var(--border); border-radius: 14px; box-shadow: var(--shadow); overflow: hidden; }
.search-panel input { width: 100%; font: 17px var(--font); padding: 16px 18px; border: 0; border-bottom: 1px solid var(--border); background: var(--bg); color: var(--fg); outline: none; }
.search-results { list-style: none; margin: 0; padding: 6px; max-height: 60vh; overflow-y: auto; }
.search-results li a { display: block; padding: 10px 12px; border-radius: 8px; color: var(--fg); }
.search-results li a:hover, .search-results li.sel a { background: color-mix(in srgb, var(--accent) 12%, transparent); text-decoration: none; }
.search-results .r-ch { font-size: 11.5px; color: var(--fg-3); text-transform: uppercase; letter-spacing: .05em; }
.search-results .r-title { font-weight: 600; }
.search-results .r-body { font-size: 13px; color: var(--fg-2); display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.search-results mark { background: color-mix(in srgb, var(--warning) 35%, transparent); color: inherit; border-radius: 2px; padding: 0 1px; }
.search-hint { margin: 0; padding: 8px 14px; font-size: 12px; color: var(--fg-3); border-top: 1px solid var(--border); display: flex; gap: 6px; align-items: center; }
.search-empty { padding: 20px; color: var(--fg-3); text-align: center; }

/* ---------- responsive ---------- */
@media (max-width: 1200px) {
  .layout { grid-template-columns: var(--sidebar-w) minmax(0, 1fr); }
  .rightbar { display: none; }
}
@media (max-width: 860px) {
  .layout { grid-template-columns: minmax(0, 1fr); }
  .menu-btn { display: flex; }
  .sidebar { position: fixed; left: 0; top: var(--topbar-h); width: min(86vw, 340px); background: var(--bg); transform: translateX(-100%); transition: transform .2s ease; z-index: 60; box-shadow: var(--shadow); }
  .sidebar.open { transform: none; }
  .content { padding: 22px 18px 48px; }
  .prose h1 { font-size: 1.9rem; }
  .search-btn span { display: none; }
  .search-btn kbd { display: none; }
  .brand span { font-size: 15px; }
  .pager { grid-template-columns: 1fr; }
}
@media print {
  .topbar, .sidebar, .rightbar, .pager, .search-modal, .copy, .anchor { display: none !important; }
  .layout { display: block; }
  .content { padding: 0; }
  .codeblock pre { white-space: pre-wrap; }
}