/* Light and dark follow the pcom app: Bootstrap's white page and system font
   stack, with the dark palette from cmd/web/client/scss/_dark-mode.scss. */
:root {
  --bg: #f8f9fa;
  --panel: #ffffff;
  --ink: #212529;
  --muted: #6c757d;
  --line: #dee2e6;
  --accent: #0d6efd;
  --accent-soft: #e7f0ff;
  --warn: #b45309;
  --error: #b91c1c;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1a1a1a; --panel: #252525; --ink: #e0e0e0; --muted: #a0a0a0;
    --line: #3a3a3a; --accent: #5dade2; --accent-soft: #1f2d3a;
    --warn: #e0a458; --error: #ef6b6b;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body { background: var(--bg); color: var(--ink); font: 15px/1.6 var(--sans); }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
code, pre, .mono { font-family: var(--mono); font-size: 13px; }
:not(pre) > code {
  background: var(--accent-soft); border-radius: 4px; padding: 1px 5px;
  overflow-wrap: anywhere;
}
.muted { color: var(--muted); }

/* topbar ---------------------------------------------------------------- */
.topbar {
  display: flex; align-items: center; gap: 18px; flex-wrap: wrap;
  padding: 10px 18px; background: var(--panel);
  border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 10;
}
.brand { font-weight: 600; color: var(--ink); font-size: 17px; }
.brand:hover { text-decoration: none; }
.topbar nav { display: flex; gap: 4px; flex-wrap: wrap; }
.topbar nav a { padding: 4px 10px; border-radius: 6px; color: var(--ink); border: 1px solid transparent; }
.topbar nav a:hover { background: var(--accent-soft); text-decoration: none; }
.topbar .spacer { flex: 1; }

/* layout ---------------------------------------------------------------- */
.layout {
  display: grid; grid-template-columns: 232px minmax(0, 1fr);
  gap: 28px; max-width: 1180px; margin: 0 auto; padding: 20px 18px 64px;
  align-items: start;
}
.sidebar { position: sticky; top: 62px; max-height: calc(100vh - 80px); overflow-y: auto; font-size: 14px; }
.sidebar > summary { display: none; }
.sidebar h2 {
  font-size: 11.5px; text-transform: uppercase; letter-spacing: .06em;
  color: var(--muted); margin: 16px 0 6px; font-weight: 600;
}
.sidebar ul { list-style: none; margin: 0; padding: 0; }
.sidebar li a {
  display: block; padding: 3px 8px; border-radius: 6px; color: var(--ink);
  overflow-wrap: anywhere;
}
.sidebar li a:hover { background: var(--accent-soft); text-decoration: none; }
.sidebar li a.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }

main { min-width: 0; max-width: 62rem; }
.doc { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 22px 26px; }
.doc > :first-child { margin-top: 0; }
h1 { font-size: 27px; line-height: 1.2; margin: 0 0 14px; }
h2 { font-size: 20px; margin: 30px 0 10px; padding-top: 4px; }
h3 { font-size: 16px; margin: 22px 0 8px; }
h4 { font-size: 15px; margin: 18px 0 6px; }
p, ul, ol { margin: 0 0 12px; }
blockquote { margin: 0 0 12px; padding: 2px 14px; border-left: 3px solid var(--line); color: var(--muted); }
hr { border: 0; border-top: 1px solid var(--line); margin: 26px 0; }

pre {
  background: var(--bg); border: 1px solid var(--line); border-radius: 8px;
  padding: 11px 13px; overflow-x: auto; margin: 0 0 14px;
}
pre code { background: none; padding: 0; }

table { border-collapse: collapse; width: 100%; margin: 0 0 14px; display: block; overflow-x: auto; }
th, td { text-align: left; padding: 7px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 500; font-size: 12px; text-transform: uppercase; letter-spacing: .04em; }

.source-note { color: var(--muted); font-size: 12.5px; margin: 0 0 18px; }
.toc { border: 1px solid var(--line); border-radius: 10px; padding: 8px 14px; margin: 0 0 20px; background: var(--bg); }
.toc > summary { cursor: pointer; color: var(--muted); font-size: 12.5px; }
.toc ul { list-style: none; margin: 8px 0 4px; padding: 0; columns: 2; column-gap: 24px; }
.toc li { break-inside: avoid; padding: 2px 0; }

.footer { max-width: 1180px; margin: 0 auto; padding: 0 18px 40px; color: var(--muted); font-size: 12.5px; }

/* landing --------------------------------------------------------------- */
.hero { max-width: 1180px; margin: 0 auto; padding: 44px 18px 10px; }
.hero h1 { font-size: 40px; letter-spacing: -.01em; }
.hero .lede { font-size: 17px; }
.hero .lede p { margin-bottom: 12px; }
.cta { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 18px; }
.cta a {
  padding: 7px 14px; border: 1px solid var(--line); border-radius: 8px;
  background: var(--panel); color: var(--ink);
}
.cta a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.cta a.primary { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); font-weight: 600; }
.landing { max-width: 1180px; margin: 0 auto; padding: 0 18px 64px; }
.landing section { margin-top: 40px; }
.landing section > h2 { font-size: 22px; margin-top: 0; }
.panel { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 18px 22px; }

.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 14px; }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; }
.card h3 { margin: 0 0 6px; font-size: 16px; display: flex; align-items: baseline; gap: 8px; }
.card h3 .title { color: var(--muted); font-size: 12px; font-weight: 400; text-transform: uppercase; letter-spacing: .05em; }
.card p { margin: 0 0 10px; }
.card .stands-for { margin: 0 0 10px; }
img { max-width: 100%; height: auto; }
.card img { display: block; width: 100%; border-radius: 8px; border: 1px solid var(--line); margin: 0 0 10px; }
.doc img { border-radius: 8px; border: 1px solid var(--line); }

@media (max-width: 860px) {
  .layout { grid-template-columns: minmax(0, 1fr); gap: 14px; padding-top: 14px; }
  .sidebar {
    position: static; max-height: none; background: var(--panel);
    border: 1px solid var(--line); border-radius: 10px; padding: 8px 12px;
  }
  .sidebar > summary { display: list-item; cursor: pointer; font-weight: 600; }
  .sidebar[open] > summary { margin-bottom: 6px; }
  .hero { padding-top: 26px; }
  .hero h1 { font-size: 32px; }
  .doc { padding: 16px 15px; }
  .toc ul { columns: 1; }
}
@media (min-width: 861px) {
  /* The sidebar is a <details> so it can collapse on a phone; on a wide
     screen it is always open, whatever the element's own state. */
  .sidebar > :not(summary) { display: block !important; }
}