:root {
  --bg: #fbfbf9;
  --bg-raised: #ffffff;
  --bg-sunken: #f2f2ee;
  --text: #1b1d1a;
  --muted: #5d635b;
  --border: #e1e2dc;
  --accent: #15803d;
  --accent-soft: #e3f3e7;
  --run: #b45309;
  --run-soft: #fdf0dc;
  --code-bg: #14171a;
  --code-text: #e4e7e2;
  --code-muted: #8b938a;
  --code-green: #6ee7a0;
  --code-amber: #fbbf63;
  --code-blue: #8ab8ff;
  --shadow: 0 1px 2px rgba(20, 24, 20, .06), 0 8px 24px rgba(20, 24, 20, .06);
  --sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --header-h: 56px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e1110;
    --bg-raised: #151918;
    --bg-sunken: #0a0c0b;
    --text: #e6e9e4;
    --muted: #9aa298;
    --border: #262b29;
    --accent: #4ade80;
    --accent-soft: #12281a;
    --run: #fbbf63;
    --run-soft: #2b2010;
    --code-bg: #0a0c0b;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px rgba(0, 0, 0, .3);
  }
}
:root[data-theme="dark"] {
  --bg: #0e1110;
  --bg-raised: #151918;
  --bg-sunken: #0a0c0b;
  --text: #e6e9e4;
  --muted: #9aa298;
  --border: #262b29;
  --accent: #4ade80;
  --accent-soft: #12281a;
  --run: #fbbf63;
  --run-soft: #2b2010;
  --code-bg: #0a0c0b;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px rgba(0, 0, 0, .3);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 16px); }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img, svg { max-width: 100%; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 20;
  height: var(--header-h);
  display: flex; align-items: center; gap: 20px;
  padding: 0 20px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--text); font-family: var(--mono); font-size: 17px; }
.brand:hover { text-decoration: none; }
.brand svg { width: 24px; height: 24px; }
.top-nav { display: flex; gap: 4px; margin-left: 8px; overflow-x: auto; scrollbar-width: none; }
.top-nav::-webkit-scrollbar { display: none; }
.top-nav a {
  color: var(--muted); font-size: 14px; padding: 6px 10px; border-radius: 6px; white-space: nowrap;
}
.top-nav a:hover { color: var(--text); background: var(--bg-sunken); text-decoration: none; }
.top-nav a[aria-current="page"] { color: var(--accent); background: var(--accent-soft); }
.header-tools { margin-left: auto; display: flex; align-items: center; gap: 6px; }
.icon-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 34px; height: 34px; border-radius: 8px;
  border: 1px solid transparent; background: none; color: var(--muted); cursor: pointer;
}
.icon-btn:hover { color: var(--text); background: var(--bg-sunken); }
.icon-btn svg { width: 18px; height: 18px; }
.menu-btn { display: none; }

/* Layout */
.layout {
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr);
  max-width: 1120px; margin: 0 auto; gap: 48px;
  padding: 0 20px;
}
.toc {
  position: sticky; top: var(--header-h);
  align-self: start;
  max-height: calc(100vh - var(--header-h));
  overflow-y: auto;
  padding: 32px 0 32px;
  font-size: 14px;
}
.toc h2 { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin: 0 0 10px; }
.toc a { display: block; padding: 4px 10px; color: var(--muted); border-left: 2px solid var(--border); }
.toc a:hover { color: var(--text); text-decoration: none; }
.toc a.active { color: var(--accent); border-left-color: var(--accent); }
.toc a.sub { padding-left: 22px; font-size: 13px; }

main { padding: 40px 0 80px; min-width: 0; }
main > h1 { font-size: 36px; line-height: 1.15; letter-spacing: -.02em; margin: 0 0 12px; }
.lede { font-size: 19px; color: var(--muted); margin: 0 0 32px; max-width: 46em; }
main h2 { font-size: 24px; letter-spacing: -.01em; margin: 56px 0 12px; padding-top: 8px; border-top: 1px solid var(--border); padding-top: 32px; }
main h2:first-of-type { border-top: 0; padding-top: 0; margin-top: 32px; }
main h3 { font-size: 18px; margin: 32px 0 8px; }
main p, main li { max-width: 46em; }
main li { margin: 4px 0; }
.anchor { margin-left: 8px; opacity: 0; color: var(--muted); font-weight: 400; }
h2:hover .anchor, h3:hover .anchor { opacity: 1; }

/* Code */
code { font-family: var(--mono); font-size: .875em; background: var(--bg-sunken); border: 1px solid var(--border); padding: .1em .35em; border-radius: 5px; }
pre {
  position: relative;
  background: var(--code-bg); color: var(--code-text);
  border-radius: 10px; padding: 16px 18px; margin: 16px 0;
  overflow-x: auto; font: 13.5px/1.6 var(--mono);
  border: 1px solid var(--border);
}
pre code { background: none; border: 0; padding: 0; font-size: inherit; color: inherit; }
pre .c { color: var(--code-muted); }
pre .g { color: var(--code-green); }
pre .a { color: var(--code-amber); }
pre .b { color: var(--code-blue); }
.copy-btn {
  position: absolute; top: 8px; right: 8px;
  font: 12px var(--sans); color: var(--code-muted);
  background: rgba(255, 255, 255, .06); border: 1px solid rgba(255, 255, 255, .1);
  border-radius: 6px; padding: 3px 8px; cursor: pointer; opacity: 0; transition: opacity .15s;
}
pre:hover .copy-btn, .copy-btn:focus { opacity: 1; }
.copy-btn:hover { color: var(--code-text); }

/* Tables */
.table-wrap { overflow-x: auto; margin: 16px 0; border: 1px solid var(--border); border-radius: 10px; }
table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--border); vertical-align: top; }
th { background: var(--bg-sunken); font-size: 12.5px; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); }
tr:last-child td { border-bottom: 0; }
td code { white-space: nowrap; }
td.wrap code { white-space: normal; }

/* Diagrams (SVG) and illustrations (webp) */
.diagram-wrap { overflow-x: auto; }
@media (max-width: 640px) { .diagram-wrap > img { min-width: 600px; } }
:root[data-theme="dark"] main img[src$=".webp"] { filter: brightness(.86); }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) main img[src$=".webp"] { filter: brightness(.86); } }

/* Callouts */
.note {
  border: 1px solid var(--border); border-left: 3px solid var(--accent);
  background: var(--bg-raised); border-radius: 8px; padding: 12px 16px; margin: 20px 0; max-width: 46em;
}
.note.warn { border-left-color: var(--run); }
.note > :first-child { margin-top: 0; }
.note > :last-child { margin-bottom: 0; }
.note strong:first-child { display: inline-block; }

/* Steps */
ol.steps { list-style: none; counter-reset: step; padding: 0; margin: 24px 0; }
ol.steps > li { counter-increment: step; position: relative; padding: 0 0 20px 48px; max-width: none; }
ol.steps > li::before {
  content: counter(step);
  position: absolute; left: 0; top: 0;
  width: 30px; height: 30px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  background: var(--accent-soft); color: var(--accent); font: 600 14px var(--mono);
}
ol.steps > li::after { content: ""; position: absolute; left: 14.5px; top: 36px; bottom: 4px; width: 1px; background: var(--border); }
ol.steps > li:last-child::after { display: none; }
ol.steps > li > h3 { margin: 2px 0 6px; font-size: 17px; }

/* Tabs */
.tabs { margin: 20px 0; }
.tab-list { display: flex; gap: 2px; border-bottom: 1px solid var(--border); overflow-x: auto; }
.tab-list button {
  font: 500 14px var(--sans); color: var(--muted);
  background: none; border: 0; border-bottom: 2px solid transparent;
  padding: 8px 14px; cursor: pointer; white-space: nowrap; margin-bottom: -1px;
}
.tab-list button:hover { color: var(--text); }
.tab-list button[aria-selected="true"] { color: var(--accent); border-bottom-color: var(--accent); }
.tab-panel[hidden] { display: none; }

/* Cards */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin: 24px 0; }
.card {
  display: block; padding: 18px; border-radius: 12px;
  border: 1px solid var(--border); background: var(--bg-raised); color: var(--text);
  transition: border-color .15s, transform .15s;
}
a.card:hover { text-decoration: none; border-color: var(--accent); transform: translateY(-1px); }
.card h3 { margin: 0 0 6px; font-size: 16px; }
.card p { margin: 0; color: var(--muted); font-size: 14.5px; line-height: 1.5; }
.card .tag { font: 12px var(--mono); color: var(--accent); }

.badge { display: inline-block; font: 600 11.5px var(--mono); padding: 2px 7px; border-radius: 5px; }
.badge.skip { background: var(--accent-soft); color: var(--accent); }
.badge.run { background: var(--run-soft); color: var(--run); }

/* Landing */
.home main { padding-top: 0; }
.home .layout { display: block; max-width: 1040px; }
.hero { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 40px; align-items: center; padding: 72px 0 48px; }
.hero h1 { font-size: clamp(34px, 5vw, 52px); line-height: 1.08; letter-spacing: -.03em; margin: 0 0 18px; }
.hero h1 em { font-style: normal; color: var(--accent); }
.hero p { font-size: 19px; color: var(--muted); margin: 0 0 26px; max-width: 30em; }
.eyebrow { font: 600 13px var(--mono); color: var(--accent); margin-bottom: 14px; }
.cta { display: flex; gap: 10px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  font-weight: 600; font-size: 15px; padding: 10px 18px; border-radius: 9px;
  border: 1px solid var(--border); color: var(--text); background: var(--bg-raised);
}
.btn:hover { text-decoration: none; border-color: var(--muted); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
:root[data-theme="dark"] .btn.primary { color: #06210f; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .btn.primary { color: #06210f; } }
.btn.primary:hover { filter: brightness(1.08); }
.term { box-shadow: var(--shadow); margin: 0; }
.term-bar { display: flex; gap: 6px; margin: -4px 0 12px; }
.term-bar i { width: 10px; height: 10px; border-radius: 50%; background: #3a403c; }
.home section { padding: 40px 0; border-top: 1px solid var(--border); }
.home section > h2 { border: 0; padding: 0; margin: 0 0 8px; font-size: 28px; }
.home section > p.sub { color: var(--muted); margin: 0 0 20px; font-size: 17px; }
.flow { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 24px; }
.flow .card .num { font: 600 13px var(--mono); color: var(--accent); display: block; margin-bottom: 8px; }
.flow pre { margin: 12px 0 0; font-size: 12.5px; padding: 10px 12px; }

footer { border-top: 1px solid var(--border); color: var(--muted); font-size: 14px; }
footer .inner { max-width: 1120px; margin: 0 auto; padding: 24px 20px; display: flex; gap: 16px; flex-wrap: wrap; justify-content: space-between; }
.pager { display: flex; justify-content: space-between; gap: 16px; margin-top: 64px; }
.pager a { flex: 1; max-width: 48%; padding: 14px 16px; border: 1px solid var(--border); border-radius: 10px; color: var(--text); }
.pager a:hover { border-color: var(--accent); text-decoration: none; }
.pager a span { display: block; font-size: 12.5px; color: var(--muted); }
.pager a.next { text-align: right; margin-left: auto; }

@media (max-width: 860px) {
  .layout { grid-template-columns: minmax(0, 1fr); gap: 0; padding: 0 16px; }
  .toc { display: none; }
  .hero { grid-template-columns: minmax(0, 1fr); padding: 40px 0 24px; }
  .flow { grid-template-columns: 1fr; }
  .menu-btn { display: inline-flex; }
  .top-nav {
    display: none; position: absolute; top: var(--header-h); left: 0; right: 0;
    flex-direction: column; margin: 0; padding: 8px 12px 12px;
    background: var(--bg); border-bottom: 1px solid var(--border);
  }
  .top-nav.open { display: flex; }
  .top-nav a { padding: 10px 12px; font-size: 15px; }
  main > h1 { font-size: 30px; }
  .site-header { padding: 0 16px; gap: 8px; }
}

/* Runner logos: always on a light tile so the black marks (Rust, Rails) stay visible in dark mode. */
.card .logo { display: inline-flex; align-items: center; justify-content: center; height: 46px; padding: 0 12px; margin-bottom: 10px; background: #fff; border: 1px solid var(--border); border-radius: 8px; }
.card .logo img { height: 26px; width: auto; max-width: 120px; display: block; }
h2 .h-logo { height: 28px; width: auto; max-width: 90px; vertical-align: -7px; margin-right: 6px; padding: 3px 6px; background: #fff; border: 1px solid var(--border); border-radius: 6px; }

/* Prism tokens, on the site's own palette (dark code blocks in both themes). */
pre code .token.comment, pre code .token.prolog, pre code .token.doctype, pre code .token.cdata { color: var(--code-muted); }
pre code .token.string, pre code .token.attr-value, pre code .token.char, pre code .token.inserted { color: var(--code-green); }
pre code .token.number, pre code .token.boolean, pre code .token.constant, pre code .token.symbol, pre code .token.deleted { color: var(--code-amber); }
pre code .token.keyword, pre code .token.atrule, pre code .token.key, pre code .token.property, pre code .token.tag, pre code .token.selector, pre code .token.table, pre code .token.class-name { color: var(--code-blue); }
pre code .token.function, pre code .token.builtin, pre code .token.function-name { color: #c7b4ff; }
pre code .token.operator, pre code .token.punctuation, pre code .token.entity, pre code .token.url { color: var(--code-text); opacity: .8; }
pre code .token.important, pre code .token.bold { font-weight: 600; }
pre code .token.parameter, pre code .token.variable { color: var(--code-text); }
pre code .token.shebang { color: var(--code-muted); }

/* Hero proof points. */
.proof { list-style: none; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px 18px; padding: 0; margin: 0 0 26px; }
.proof li { display: flex; flex-direction: column; gap: 2px; }
.proof strong { font-size: 24px; letter-spacing: -.02em; color: var(--accent); line-height: 1.1; }
.proof span { font-size: 13px; color: var(--muted); line-height: 1.4; }
.proof sup a { text-decoration: none; color: var(--muted); }
.hero p strong { color: var(--text); }

/* Bar charts (benchmarks): plain HTML, so they reflow on a phone and take the theme's colours. */
.barchart { margin: 20px 0 24px; max-width: 46em; }
.barchart figcaption { font-size: 14px; color: var(--muted); margin: 0 0 12px; }
.bar-row { display: grid; grid-template-columns: minmax(0, 17em) minmax(0, 1fr) 5.5em; gap: 2px 12px; align-items: center; margin: 8px 0; font-size: 14px; line-height: 1.35; }
.bar-label small { display: block; color: var(--muted); font-size: 12.5px; }
.bar-track { height: 14px; background: var(--bg-sunken); border: 1px solid var(--border); border-radius: 4px; overflow: hidden; }
.bar { display: block; height: 100%; background: var(--accent); }
.bar.before { background: var(--run); }
.bar.plain { background: var(--muted); }
.bar-value { font: 600 13.5px var(--mono); text-align: right; white-space: nowrap; }
.legend { display: flex; flex-wrap: wrap; gap: 6px 18px; font-size: 13px; color: var(--muted); margin: 4px 0 0; }
.legend span::before { content: ""; display: inline-block; width: 11px; height: 11px; border-radius: 3px; margin-right: 6px; vertical-align: -1px; background: var(--accent); }
.legend .before::before { background: var(--run); }
.legend .plain::before { background: var(--muted); }
@media (max-width: 640px) {
  .bar-row { grid-template-columns: minmax(0, 1fr) auto; margin: 12px 0; }
  .bar-label { grid-column: 1 / -1; }
}