:root {
  --bg: #f7f8fa; --panel: #ffffff; --text: #1d2330; --weak: #5d6575; --line: #d8dde6; --accent: #2f6fcf;
  --faint: #eef1f6; --code: #eef1f6; --formula: #f3f5f9; --note: #f0f5ff; --head: #e7ecf4; --current: #dfe9fb;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #1a1c20; --panel: #202227; --text: #dde1e8; --weak: #9aa1ad; --line: #3a3e47; --accent: #78aef0;
    --faint: #262930; --code: #2a2d35; --formula: #15171a; --note: #1f2a3a; --head: #2b2f38; --current: #24364f;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body { background: var(--bg); color: var(--text); font: 16px/1.6 "Segoe UI", "Noto Sans", "DejaVu Sans", Ubuntu, Arial, sans-serif; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
header { position: sticky; top: 0; z-index: 2; display: flex; flex-wrap: wrap; gap: 8px 24px; align-items: center;
  padding: 10px 16px; background: var(--panel); border-bottom: 1px solid var(--line); }
header .brand { font-weight: 700; font-size: 18px; color: var(--text); display: inline-flex; align-items: center; gap: 8px; }
header nav.top a { margin-right: 16px; }
header form.search { margin-left: auto; }
header input { width: 240px; max-width: 60vw; padding: 6px 10px; border: 1px solid var(--line); border-radius: 6px; background: var(--bg); color: var(--text); font: inherit; }
.layout { display: grid; grid-template-columns: minmax(220px, 300px) 1fr; min-height: calc(100vh - 110px); }
nav.toc { border-right: 1px solid var(--line); padding: 12px 8px 24px 8px; background: var(--panel); position: sticky; top: 55px; align-self: start; height: calc(100vh - 55px); overflow: auto; font-size: 14.5px; }
nav.toc ul { list-style: none; margin: 0; padding-left: 14px; }
nav.toc > ul { padding-left: 4px; }
nav.toc li { margin: 1px 0; }
nav.toc li.current > a { background: var(--current); border-radius: 4px; padding: 1px 6px; margin-left: -6px; font-weight: 600; }
nav.toc summary { cursor: pointer; font-weight: 600; color: var(--text); padding: 2px 0; }
main { padding: 16px 28px 32px 28px; min-width: 0; }
article { max-width: 920px; }
.crumbs { color: var(--weak); font-size: 14px; }
h1 { font-size: 28px; margin: 4px 0 12px 0; }
h2 { font-size: 21px; margin: 28px 0 8px 0; padding-bottom: 4px; border-bottom: 1px solid var(--line); }
h3 { font-size: 17px; margin: 20px 0 6px 0; }
code { background: var(--code); padding: 1px 5px; border-radius: 4px; font: 14px/1.4 "Cascadia Mono", Consolas, "DejaVu Sans Mono", monospace; }
pre { background: var(--formula); border: 1px solid var(--line); border-radius: 6px; padding: 10px 14px; overflow-x: auto; }
pre code { background: none; padding: 0; }
.formula { background: var(--formula); border: 1px solid var(--line); border-radius: 6px; padding: 10px 18px; margin: 10px 0;
  font-family: "Cambria Math", "STIX Two Math", "Latin Modern Math", "Times New Roman", "DejaVu Serif", serif; font-size: 17px; overflow-x: auto; }
.formula div { white-space: pre; }
.note { background: var(--note); border-left: 4px solid var(--accent); padding: 8px 14px; border-radius: 4px; margin: 10px 0; }
.table { overflow-x: auto; margin: 10px 0; }
table { border-collapse: collapse; font-size: 15px; }
th, td { border: 1px solid var(--line); padding: 5px 9px; vertical-align: top; text-align: left; }
thead th { background: var(--head); }
tbody tr:nth-child(odd) { background: var(--faint); }
figure { margin: 14px 0; }
figure img { max-width: 100%; height: auto; border: 1px solid var(--line); border-radius: 4px; }
figcaption { color: var(--weak); font-style: italic; font-size: 14.5px; }
a.cite { white-space: nowrap; }
.anchor { display: block; position: relative; top: -64px; visibility: hidden; }
.pager { display: flex; justify-content: space-between; gap: 16px; max-width: 920px; margin-top: 28px; padding-top: 12px; border-top: 1px solid var(--line); }
.pager .next { margin-left: auto; }
ul.index { columns: 2 320px; }
ul.index .where { color: var(--weak); font-size: 13.5px; }
ol.results li { margin-bottom: 10px; }
ol.results p { margin: 2px 0; color: var(--weak); font-size: 14.5px; }
.foot { color: var(--weak); font-size: 13px; padding: 10px 16px; border-top: 1px solid var(--line); background: var(--panel); }
@media (max-width: 760px) {
  .layout { grid-template-columns: 1fr; }
  nav.toc { position: static; max-height: none; border-right: none; border-bottom: 1px solid var(--line); }
  main { padding: 12px 16px; }
  header form.search { margin-left: 0; }
}