/* 颜色、间距与阅读宽度集中在这里，正文和交互实验共用同一组主题。 */
:root {
  color-scheme: light;
  --paper: #ffffff;
  --surface: #f7f8fa;
  --subtle: #f0f2f5;
  --ink: #222e40;
  --muted: #657286;
  --line: #e3e7ec;
  --accent: #c54825;
  --accent-bright: #e45b34;
  --accent-soft: #fff2eb;
  --blue: #397cba;
  --green: #268370;
  --code: #192333;
  --code-ink: #e2e9f3;
  --shadow: 0 20px 70px #14203024;
  --sidebar: 252px;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.85;
  font-synthesis: none;
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #141a24;
  --surface: #1a2230;
  --subtle: #232d3c;
  --ink: #e0e7f1;
  --muted: #a1aec0;
  --line: #303c4f;
  --accent: #ff9a77;
  --accent-bright: #f07c56;
  --accent-soft: #332720;
  --blue: #81b8ef;
  --green: #6bc5af;
  --code: #0f1520;
  --shadow: 0 20px 70px #0008;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--paper); color: var(--ink); }
button, input, select { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; color: inherit; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 4px; }
a:hover { text-decoration: underline; }
button:disabled { opacity: .55; cursor: default; }
:focus-visible { outline: 3px solid var(--blue); outline-offset: 4px; }
[hidden] { display: none !important; }
p { margin: 12px 0 20px; }
strong { font-weight: 650; }
code, pre, kbd, .metrics strong, .state-cards strong {
  font-family: "Cascadia Code", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}
:not(pre) > code { font-size: .87em; background: var(--subtle); padding: 2px 5px; border-radius: 4px; overflow-wrap: anywhere; }
input[type="range"] { display: block; width: 100%; accent-color: var(--accent-bright); margin: 12px 0 22px; cursor: pointer; }
input[type="checkbox"] { accent-color: var(--accent); width: 17px; height: 17px; }
.skip-link { position: fixed; top: -60px; left: 20px; z-index: 100; background: var(--paper); padding: 10px 20px; }
.skip-link:focus { top: 8px; }
.site-header { height: 76px; position: sticky; top: 0; z-index: 30; display: flex; align-items: center; gap: 40px; padding: 0 32px; border-bottom: 1px solid var(--line); background: var(--paper); }
.brand { display: inline-flex; gap: 10px; align-items: center; text-decoration: none; color: var(--ink); font-size: 22px; font-weight: 680; letter-spacing: -.7px; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.brand-mark { width: 30px; height: 32px; font-size: 27px; line-height: 30px; color: var(--accent-bright); letter-spacing: -5px; font-weight: 750; }
.brand-mark span { color: var(--ink); }
.brand-section { margin-left: 4px; color: var(--muted); font-size: 15px; font-weight: 400; letter-spacing: 0; }
.top-links { display: flex; gap: 28px; height: 100%; align-items: center; }
.top-links a { color: var(--muted); text-decoration: none; font-size: 14px; height: 100%; display: flex; align-items: center; border-bottom: 2px solid transparent; }
.top-links a.current { color: var(--ink); border-color: var(--accent-bright); }
.header-actions { display: flex; align-items: center; gap: 18px; margin-left: auto; }
.search-trigger { background: var(--surface); border: 1px solid var(--line); border-radius: 6px; padding: 5px 10px; display: flex; align-items: center; gap: 12px; color: var(--muted); font-size: 13px; }
.search-trigger > span:first-child { font-size: 24px; line-height: 26px; }
kbd { border: 1px solid var(--line); border-radius: 4px; padding: 1px 5px; font-size: 11px; color: var(--muted); font-weight: 400; }
.icon-button { padding: 4px; min-width: 32px; min-height: 32px; background: transparent; border: 0; font-size: 22px; line-height: 1; }
.github-link { font-size: 13px; color: var(--ink); text-decoration: none; white-space: nowrap; }
.menu-button { display: none; }
.page-shell { display: grid; grid-template-columns: var(--sidebar) minmax(0, 900px) 204px; justify-content: center; max-width: 1600px; margin: auto; }
.sidebar { position: sticky; top: 76px; height: calc(100vh - 76px); padding: 34px 20px 24px 28px; border-right: 1px solid var(--line); overflow-y: auto; scrollbar-width: thin; }
.sidebar-title { font-size: 13px; margin-bottom: 20px; color: var(--ink); font-weight: 700; }
.nav-group { font-weight: 650; font-size: 13px; margin: 20px 0 7px 10px; }
.nav-group:first-child { margin-top: 0; }
:is(#lesson-nav, #document-nav) a { display: flex; gap: 12px; align-items: center; border-left: 2px solid transparent; border-radius: 0 5px 5px 0; padding: 7px 9px; font-size: 14px; color: var(--ink); text-decoration: none; line-height: 1.6; margin: 2px 0; }
:is(#lesson-nav, #document-nav) a:hover { background: var(--surface); color: var(--ink); }
:is(#lesson-nav, #document-nav) a[aria-current="page"] { background: var(--accent-soft); border-left-color: var(--accent-bright); color: var(--accent); font-weight: 600; }
.lesson-number { font-family: Consolas, monospace; font-size: 11px; opacity: .8; }
.done-mark { margin-left: auto; color: var(--green); }
.course-progress { display: flex; flex-wrap: wrap; justify-content: space-between; margin: 24px 10px; font-size: 13px; color: var(--ink); }
.course-progress strong { color: var(--ink); }
.course-progress progress { width: 100%; height: 4px; appearance: none; background: var(--line); border: 0; margin: 9px 0; }
progress::-webkit-progress-bar { background: var(--line); border-radius: 4px; }
progress::-webkit-progress-value { background: var(--accent-bright); border-radius: 4px; }
progress::-moz-progress-bar { background: var(--accent-bright); }
.sidebar-reference { display: flex; justify-content: space-between; margin: 0 10px; padding-top: 16px; border-top: 1px solid var(--line); color: var(--ink); font-size: 13px; text-decoration: none; }
main { min-width: 0; padding: 28px 46px 24px; }
.breadcrumb { display: flex; gap: 12px; align-items: center; font-size: 13px; color: var(--ink); margin-bottom: 34px; }
.breadcrumb span { color: var(--muted); }
.breadcrumb strong { font-weight: 500; color: var(--ink); }
.lesson { scroll-margin-top: 100px; }
h1 { font-size: 34px; line-height: 1.4; font-weight: 680; letter-spacing: -.5px; margin: 18px 0 16px; }
.lead { font-size: 16px; line-height: 1.9; color: var(--ink); max-width: 690px; margin-bottom: 20px; }
.math { font-family: Georgia, "Times New Roman", serif; font-size: 1.15em; font-style: italic; white-space: nowrap; }
h2 { font-size: 23px; font-weight: 650; margin: 40px 0 14px; line-height: 1.5; letter-spacing: -.6px; scroll-margin-top: 100px; }
.note { padding: 18px 22px; border-left: 3px solid var(--accent-bright); background: var(--accent-soft); margin: 28px 0; border-radius: 0 6px 6px 0; font-size: 14px; }
.note p { margin: 5px 0 0; }
pre { margin: 0 0 24px; padding: 21px 22px; background: var(--code); color: var(--code-ink); overflow: auto; font-size: 13px; line-height: 1.85; tab-size: 4; border-radius: 7px; }
pre code { font-family: inherit; }
.code-toolbar { display: flex; gap: 16px; align-items: center; background: var(--code); color: #a1afc3; padding: 10px 16px; font-size: 12px; border-bottom: 1px solid #ffffff18; border-radius: 7px 7px 0 0; }
.code-toolbar + pre { border-radius: 0 0 7px 7px; }
.code-toolbar > span { margin-right: auto; letter-spacing: .5px; }
.code-toolbar a, .code-toolbar button { color: #c1ccdc; font-size: 12px; text-decoration: none; }
.code-toolbar button { background: transparent; border: 0; padding: 0 4px; }
.syntax-keyword { color: #afc4fc; }
.syntax-string { color: #e1ba91; }
.syntax-comment { color: #8da99e; }
.tabs { display: flex; gap: 20px; margin-top: 12px; border-bottom: 1px solid var(--line); margin-bottom: 14px; }
.tabs button { border: 0; background: none; padding: 8px 0; border-bottom: 2px solid transparent; font-size: 12px; color: var(--muted); }
.tabs button[aria-selected="true"] { color: var(--accent); border-bottom-color: var(--accent); }
table { display: block; overflow-x: auto; border-collapse: collapse; width: 100%; font-size: 14px; margin: 20px 0 28px; }
th { text-align: left; font-weight: 600; background: var(--surface); }
td, th { padding: 13px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
td:first-child { min-width: 118px; }
.lab { border: 1px solid var(--line); border-radius: 9px; padding: 24px; margin: 22px 0 28px; background: var(--surface); }
.lab-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; font-size: 13px; color: var(--ink); margin-bottom: 24px; }
.lab-tag { color: var(--accent); background: var(--accent-soft); border: 1px solid color-mix(in srgb, var(--accent) 16%, transparent); padding: 2px 8px; border-radius: 4px; font-weight: 600; letter-spacing: .3px; }
.workflow { display: flex; align-items: center; gap: 6px; }
.workflow button { flex: 1; min-width: 0; border: 1px solid var(--line); background: var(--paper); border-radius: 6px; padding: 10px 3px; font-size: 12px; white-space: nowrap; }
.workflow button span { display: block; font: 11px Consolas, monospace; color: var(--muted); margin-bottom: 5px; }
.workflow button.selected { border-color: var(--accent); background: var(--accent-soft); color: var(--accent); }
.flow-arrow { color: var(--muted); font-size: 14px; }
.workflow-detail { margin-top: 24px; padding-top: 18px; border-top: 1px solid var(--line); min-height: 120px; }
.workflow-detail code { font-size: 12px; padding: 0; background: none; }
.workflow-detail p { font-size: 14px; color: var(--ink); margin: 9px 0 0; }
.button { border: 1px solid var(--line); background: var(--paper); border-radius: 5px; padding: 8px 15px; font-size: 14px; font-weight: 600; white-space: nowrap; }
.button:hover { border-color: var(--muted); }
.button.primary { background: var(--accent); border-color: var(--accent); color: var(--paper); }
:root[data-theme="dark"] .button.primary { color: #201d1b; }
.button.quiet { border-color: transparent; background: none; color: var(--muted); }
.button.small { padding: 4px 10px; font-size: 13px; }
.lab-controls { display: flex; align-items: center; flex-wrap: wrap; gap: 10px; margin-top: 20px; }
.status { font-size: 14px; color: var(--ink); margin-left: auto; }
.lab-caption { font-size: 14px; color: var(--ink); margin: 18px 0 0; line-height: 1.8; }
.field-label { font-size: 14px; color: var(--ink); display: block; margin-bottom: 10px; }
.layout-demo { display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 28px; margin-bottom: 24px; min-height: 220px; }
.tensor-grid { display: grid; gap: 7px; max-width: 260px; }
.tensor-grid button { min-width: 0; border: 1px solid var(--line); background: var(--paper); border-radius: 6px; padding: 8px; font-size: 19px; font-family: Consolas, monospace; }
.tensor-grid button small { display: block; color: var(--muted); font: 12px Consolas, monospace; }
.tensor-grid button.selected, .storage-strip .selected { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.layout-metadata code { display: block; background: none; padding: 4px 0; font-size: 13px; }
.layout-metadata p { font: 12px/1.9 Consolas, monospace; color: var(--ink); margin-top: 18px; }
.storage-strip { display: grid; grid-template-columns: repeat(6, 1fr); gap: 6px; }
.storage-strip > span { text-align: center; background: var(--paper); border: 1px solid var(--line); padding: 7px; border-radius: 4px; font: 18px Consolas, monospace; }
.storage-strip small { display: block; color: var(--muted); font-size: 12px; margin-top: 6px; }
.range-label { font-size: 14px; display: flex; align-items: center; justify-content: space-between; }
.range-label output { font: 600 14px Consolas, monospace; color: var(--accent); }
.gradient-paths { display: flex; justify-content: center; align-items: center; gap: 28px; padding: 10px 0 20px; }
.math-node { border: 1px solid var(--line); border-radius: 7px; text-align: center; min-width: 68px; padding: 10px; font-family: Consolas, monospace; background: var(--paper); }
.math-node > span { display: block; font-size: 20px; }
.math-node.accent { border-color: var(--accent); color: var(--accent); }
.path-branches { flex: 1; max-width: 280px; }
.path-branches > div { padding: 12px 0; border-bottom: 1px solid var(--line); display: flex; justify-content: space-between; gap: 10px; font-family: Consolas, monospace; }
.path-branches > div > span { font-size: 14px; color: var(--ink); }
.formula { text-align: center; padding: 15px 0; font-size: 17px; }
.formula strong { color: var(--accent); font-size: 24px; }
.training-charts { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; }
figure { margin: 0; min-width: 0; }
figcaption { font-size: 14px; color: var(--ink); margin-bottom: 4px; display: flex; align-items: center; gap: 8px; }
.training-charts svg { width: 100%; display: block; }
svg .chart-grid { stroke: var(--line); stroke-width: 1; }
svg .chart-axis { stroke: var(--muted); stroke-width: 1; opacity: .5; }
svg text { fill: var(--ink); font: 16px Consolas, monospace; }
svg .prediction { stroke: var(--accent-bright); stroke-width: 3; fill: none; }
svg .data-point { fill: var(--blue); stroke: var(--surface); stroke-width: 3; }
svg .loss-line { stroke: var(--green); stroke-width: 2.5; fill: none; }
.legend-dot { width: 7px; height: 7px; border-radius: 50%; display: inline-block; background: var(--blue); }
.legend-line { width: 14px; height: 2px; background: var(--accent-bright); margin-left: 7px; }
.metrics { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; padding: 20px 0; margin: 10px 0 16px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.metrics span { font-size: 14px; color: var(--ink); display: block; }
.metrics strong { display: block; font-size: 20px; font-weight: 500; margin-top: 3px; }
.metrics.two { grid-template-columns: 1fr 1fr; text-align: center; margin-bottom: 0; }
.equation-card { display: grid; gap: 12px; padding: 22px; background: var(--surface); border-radius: 7px; font-size: 16px; overflow-x: auto; }
.equation-card > .update-rule { border-top: 1px solid var(--line); padding-top: 14px; color: var(--accent); font-weight: 500; }
.probability-bars { display: grid; grid-template-columns: auto minmax(0, 1fr) 64px; align-items: center; gap: 12px; margin: 24px 0; }
.probability-bars progress { width: 100%; height: 14px; appearance: none; background: var(--line); border: 0; }
.probability-bars output { text-align: right; font-family: Consolas, monospace; }
.target-label { display: flex; align-items: center; gap: 18px; }
.target-label select { background: var(--paper); color: var(--ink); border: 1px solid var(--line); border-radius: 4px; padding: 4px 10px; }
.exercise { border: 1px solid var(--line); border-radius: 6px; padding: 16px 20px; margin: 26px 0; }
.exercise summary { cursor: pointer; font-weight: 600; }
.exercise p { margin-bottom: 0; }
.link-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin: 22px 0; }
.link-cards a { border: 1px solid var(--line); border-radius: 6px; padding: 18px; text-decoration: none; color: var(--ink); }
.link-cards a:hover { border-color: var(--accent); }
.link-cards strong { display: flex; justify-content: space-between; gap: 15px; font-size: 13px; }
.link-cards strong span { color: var(--accent); }
.link-cards p { font-size: 14px; color: var(--ink); margin: 7px 0 0; }
.binding-switch { display: flex; gap: 14px; }
.binding-switch button { text-align: left; flex: 1; border: 1px solid var(--line); background: var(--paper); border-radius: 6px; padding: 16px; font-size: 13px; }
.binding-switch small { display: block; font-size: 14px; color: var(--ink); margin-top: 6px; }
.binding-switch .selected { border-color: var(--accent); background: var(--accent-soft); color: var(--accent); }
.binding-switch + .formula { margin-top: 24px; }
.state-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.state-cards > div { border: 1px solid var(--line); background: var(--paper); text-align: center; padding: 16px 8px; border-radius: 6px; }
.state-cards code { background: none; font-size: 12px; padding: 0; }
.state-cards strong { display: block; font-size: 34px; font-weight: 500; margin: 10px 0; }
.state-cards span { font-size: 14px; color: var(--ink); }
.state-cards .snapshot-card { border-color: var(--accent); }
.snapshot-card strong { color: var(--accent); }
.check-label { display: flex; align-items: center; gap: 7px; }
.plan-flow { display: flex; align-items: center; justify-content: center; gap: 20px; min-height: 120px; font: 13px Consolas, monospace; }
.plan-inputs { display: grid; gap: 10px; }
.plan-inputs code, .plan-flow > code { padding: 7px 12px; border: 1px solid var(--line); background: var(--paper); text-align: center; }
.plan-operations { display: flex; align-items: center; gap: 8px; }
.operation { border: 1px solid var(--line); border-radius: 5px; padding: 14px; background: var(--paper); font-size: 12px; }
.operation.fused { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.toc { position: sticky; top: 76px; height: fit-content; max-height: calc(100vh - 76px); overflow-y: auto; padding: 48px 20px 20px 8px; font-size: 13px; }
.toc-title { font-weight: 600; padding-left: 15px; margin-bottom: 10px; }
#page-toc { border-left: 1px solid var(--line); }
#page-toc a { display: block; padding: 7px 14px; margin-left: -1px; border-left: 2px solid transparent; color: var(--muted); text-decoration: none; line-height: 1.8; }
#page-toc a.active { border-color: var(--accent); color: var(--accent); }
.toc-source { display: block; margin: 28px 0 24px 15px; color: var(--muted); text-decoration: none; }
.lesson-completion { display: flex; align-items: center; gap: 15px; border-top: 1px solid var(--line); padding-top: 28px; margin-top: 44px; }
.lesson-completion button[aria-pressed="true"] { border-color: var(--green); color: var(--green); }
.lesson-pagination { display: flex; justify-content: space-between; gap: 20px; margin: 34px 0; }
.lesson-pagination a { min-width: 0; width: 50%; padding: 15px 18px; border: 1px solid var(--line); border-radius: 6px; color: var(--ink); text-decoration: none; }
.lesson-pagination a:last-child { text-align: right; margin-left: auto; }
.lesson-pagination a:hover { border-color: var(--accent); }
.lesson-pagination small { display: block; color: var(--ink); font-size: 13px; }
.lesson-pagination strong { font-size: 14px; font-weight: 500; }
.article-footer { display: flex; gap: 18px; align-items: center; flex-wrap: wrap; padding: 24px 0 10px; border-top: 1px solid var(--line); color: var(--ink); font-size: 13px; }
.article-footer a { color: var(--muted); text-decoration: none; }
.text-button { padding: 0; border: 0; background: none; font-size: inherit; color: var(--muted); }
dialog { width: min(580px, calc(100% - 30px)); margin-top: min(15vh, 140px); padding: 24px; border: 1px solid var(--line); border-radius: 12px; background: var(--paper); color: var(--ink); box-shadow: var(--shadow); }
dialog::backdrop { background: #111d2c66; backdrop-filter: blur(3px); }
.search-top { display: flex; justify-content: space-between; align-items: center; font-size: 14px; margin-bottom: 16px; }
#search-input { width: 100%; border: 1px solid var(--line); border-radius: 5px; background: var(--surface); padding: 10px 12px; color: var(--ink); font-size: 14px; }
#search-results { margin-top: 14px; max-height: 45vh; overflow-y: auto; }
#search-results a { display: block; text-decoration: none; color: var(--ink); padding: 12px; border-radius: 5px; }
#search-results a:hover, #search-results a:focus-visible { background: var(--surface); }
#search-results strong { display: block; font-size: 13px; }
#search-results p { color: var(--ink); font-size: 13px; margin: 3px 0 0; }
.search-empty { color: var(--muted); padding: 20px 10px; font-size: 13px; }
.search-footer { display: flex; justify-content: space-between; font-size: 13px; color: var(--ink); padding-top: 18px; border-top: 1px solid var(--line); margin-top: 14px; }
.toast { position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%); z-index: 70; padding: 9px 18px; border: 1px solid var(--line); border-radius: 6px; background: var(--ink); color: var(--paper); box-shadow: var(--shadow); font-size: 12px; }
.noscript { position: fixed; bottom: 0; padding: 10px; background: var(--paper); border-top: 1px solid var(--line); width: 100%; font-size: 12px; text-align: center; }
.muted { color: var(--muted); }
@media (min-width: 1600px) { .page-shell { border-right: 1px solid var(--line); } }
@media (max-width: 1200px) {
  :root { --sidebar: 230px; }
  .page-shell { grid-template-columns: var(--sidebar) minmax(0, 1fr); }
  .toc { display: none; }
  main { padding: 28px 40px; max-width: 880px; }
  .site-header { gap: 30px; padding: 0 24px; }
  .top-links { gap: 22px; }
  .github-link { display: none; }
}
@media (max-width: 800px) {
  .site-header { height: 64px; gap: 14px; padding: 0 18px; }
  .brand { font-size: 20px; }
  .brand-section { font-size: 13px; margin-left: 0; }
  .top-links { display: none; }
  .header-actions { gap: 12px; }
  .search-trigger { background: none; border: 0; padding: 0 4px; }
  .search-label, .search-trigger kbd { display: none; }
  .menu-button { display: block; }
  .page-shell { display: block; }
  .sidebar { display: none; position: fixed; top: 64px; left: 0; height: calc(100dvh - 64px); width: 268px; z-index: 40; background: var(--paper); padding-top: 24px; }
  body.menu-open .sidebar { display: block; }
  .sidebar-scrim { position: fixed; inset: 64px 0 0; background: #0c142d66; border: 0; z-index: 35; }
  main { padding: 22px 24px; }
  .breadcrumb { margin-bottom: 26px; }
  h1 { font-size: 32px; letter-spacing: -1px; }
  h2 { font-size: 22px; scroll-margin-top: 85px; }
  .lead { font-size: 16px; }
  .lab { padding: 20px; }
}
@media (max-width: 480px) {
  :root { font-size: 15px; }
  main { padding: 20px; }
  .site-header { padding: 0 14px; gap: 10px; }
  .brand { gap: 6px; }
  .brand-section { display: none; }
  h1 { font-size: 28px; }
  .lab { padding: 16px; }
  .lab-heading { margin-bottom: 20px; }
  .workflow { gap: 4px; }
  .flow-arrow { display: none; }
  .workflow { flex-wrap: wrap; }
  .workflow button { flex: 1 1 28%; font-size: 13px; padding: 9px 3px; }
  .workflow-detail { min-height: 135px; }
  .workflow-detail code { font-size: 12px; }
  .layout-demo { grid-template-columns: 1fr; gap: 18px; }
  .tensor-grid { margin: auto; }
  .layout-metadata { text-align: center; }
  .training-charts { grid-template-columns: 1fr; gap: 20px; }
  .metrics { grid-template-columns: 1fr 1fr; gap: 16px; }
  .metrics strong { font-size: 21px; }
  .gradient-paths { gap: 10px; }
  .math-node { min-width: 48px; padding: 8px; }
  .path-branches > div { font-size: 12px; }
  .path-branches > div > span { font-size: 14px; }
  .link-cards { grid-template-columns: 1fr; }
  .state-cards { grid-template-columns: 1fr; gap: 12px; }
  .state-cards code { font-size: 12px; }
  .state-cards span { font-size: 14px; }
  .binding-switch { gap: 10px; }
  .binding-switch button { padding: 12px; }
  .plan-flow { gap: 8px; font-size: 11px; }
  .plan-inputs code, .plan-flow > code { padding: 5px; }
  .operation { padding: 12px 7px; font-size: 12px; }
  .plan-operations { gap: 4px; }
  .status { margin-left: 0; width: 100%; }
  td, th { padding: 10px 7px; }
  td:first-child { min-width: 90px; }
  table { font-size: 14px; }
  .lesson-completion { gap: 10px; flex-wrap: wrap; }
  .lesson-pagination { gap: 12px; }
  .lesson-pagination a { padding: 12px; }
  .equation-card { font-size: 13px; padding: 18px; }
  pre { font-size: 13px; padding: 18px; }
}
@media (prefers-reduced-motion: no-preference) {
  .button, .workflow button, :is(#lesson-nav, #document-nav) a { transition: background .15s, border-color .15s; }
}
@media print {
  .site-header, .sidebar, .toc, .breadcrumb, .lesson-completion, .lesson-pagination, .article-footer, .lab-controls, .code-toolbar, .tabs, .toast, .noscript { display: none !important; }
  .page-shell { display: block; }
  main { max-width: none; padding: 0; }
  body { background: white; color: black; }
  pre { white-space: pre-wrap; color: black; background: #f4f4f4; }
  .lab, pre, table { break-inside: avoid; }
  a { color: inherit; }
}

/* 数学公式沿用数学字体；长公式与源文件在各自容器中横向滚动。 */
.katex { font-size: 1.08em; }
.math-display { display: block; overflow-x: auto; overflow-y: hidden; }
.math-display .katex-display { margin: .5em 0; text-align: left; }
.formula strong { font-family: KaTeX_Main, "Times New Roman", serif; font-weight: 400; }
.reader h1 { overflow-wrap: anywhere; }
.reader pre { margin-bottom: 28px; }
.reader .code-toolbar + pre { margin-top: 0; }
.reader article { padding-bottom: 28px; }
#page-toc .toc-depth-3 { padding-left: 26px; }