/* learn-regression 样式：一页面试速查 */
@import url("https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;600&family=Source+Serif+4:ital,opsz,wght@0,8..60,400;0,8..60,600;1,8..60,400&family=JetBrains+Mono:wght@400;500&display=swap");

:root {
  --bg: #fffdf7;
  --fg: #1f1d1a;
  --muted: #6d685e;
  --rule: #e3ddcf;
  --panel: #f6f2e8;
  --accent: #a3391b;
  --c2: #2b6a8f;
  --c1-soft: #f4e2d8;
  --c2-soft: #dde9f1;
  --ok: #2e7d4f;
  --serif: "Source Serif 4", "Noto Serif SC", Georgia, "Songti SC", "SimSun", serif;
  --mono: "JetBrains Mono", Consolas, monospace;
  --ui: "Segoe UI", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #161513;
    --fg: #e9e5dc;
    --muted: #a39d90;
    --rule: #37342e;
    --panel: #201e1b;
    --accent: #ec9a74;
    --c2: #86bbdc;
    --c1-soft: #3a2a22;
    --c2-soft: #1e2d38;
    --ok: #7cc79a;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #161513;
  --fg: #e9e5dc;
  --muted: #a39d90;
  --rule: #37342e;
  --panel: #201e1b;
  --accent: #ec9a74;
  --c2: #86bbdc;
  --c1-soft: #3a2a22;
  --c2-soft: #1e2d38;
  --ok: #7cc79a;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scrollbar-color: var(--rule) transparent; }
::selection { background: var(--c1-soft); color: var(--fg); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 3px; }
input, select { caret-color: var(--accent); }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.75;
  overflow-x: hidden;
}
main { max-width: 46rem; margin: 0 auto; padding: 2.5rem 16px 5rem; }

h1 { font-size: 2rem; line-height: 1.3; font-weight: 600; letter-spacing: -.01em; text-wrap: balance; margin: 0 0 .9rem; }
h2 { font-size: 1.15rem; font-weight: 600; text-wrap: balance; margin: 2.4rem 0 .6rem; padding-top: .9rem; border-top: 1px solid var(--rule); }
h3 { font-size: 1rem; font-weight: 600; margin: 1.2rem 0 .4rem; }
p { margin: 0 0 .9rem; }
a { color: var(--accent); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
/* overflow-wrap：很长的标识符（比如 reduce_from_tensor_model_parallel_region）在手机上可以折行，pre 里的代码不受影响 */
code { font-family: var(--mono); font-size: .85em; background: var(--panel); padding: .08em .35em; border-radius: 3px; font-variant-ligatures: none; overflow-wrap: anywhere; }
strong { font-weight: 600; }
ul, ol { padding-left: 1.3rem; margin: 0 0 .9rem; }
li { margin: .2rem 0; }

/* 题目下方的元信息：英文问法、考过 */
.meta { font-size: .9rem; color: var(--muted); line-height: 1.65; margin: 0 0 .4rem; }
.meta b { color: var(--fg); font-weight: 600; margin-right: .4rem; }
.meta q { font-style: italic; }

/* 概念解释：术语 + 中文形象说明 + 例子 */
.concepts { margin: .4rem 0 1rem; }
.concepts dt { font-weight: 600; margin-top: .9rem; }
.concepts dd { margin: .2rem 0 0; padding-left: .9rem; border-left: 1px solid var(--rule); }
.concepts .eg { display: block; color: var(--muted); font-size: .94rem; margin-top: .15rem; }

/* 30 秒英文答案 */
.answer { border: 1px solid var(--rule); background: var(--panel); border-radius: 8px; padding: 1rem 1.2rem; margin: .4rem 0 1rem; }
.answer p { font-style: italic; margin: 0; }

/* 推导：紧凑的独立公式，中间夹一行说明 */
.deriv .katex-display { margin: .5rem 0; }
.deriv p { font-size: .94rem; color: var(--muted); margin: .2rem 0 .4rem; }

/* 追问：问题可见，点开看答案，顺便自测 */
details { border: 1px solid var(--rule); border-radius: 6px; padding: .5rem .9rem; margin: .45rem 0; }
details > summary { cursor: pointer; font-weight: 600; font-size: .96rem; }
details > summary::marker { color: var(--muted); }
details[open] > summary { margin-bottom: .45rem; }
details > :last-child { margin-bottom: 0; }
details p, details li { font-size: .95rem; }

/* 全站导航（nav.js 生成） */
.sitebar { font-family: var(--ui); display: flex; flex-wrap: wrap; align-items: baseline; gap: .4rem 1rem; font-size: .85rem; color: var(--muted); padding-bottom: .6rem; margin-bottom: 1.6rem; border-bottom: 1px solid var(--rule); }
.sitebar a { color: var(--muted); }
.sitebar a:hover { color: var(--accent); }
.sitebar .home { font-weight: 600; color: var(--fg); }
.sitebar .step { margin-left: auto; display: flex; gap: .9rem; }
.pager { font-family: var(--ui); display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; margin-top: 2.4rem; padding-top: .9rem; border-top: 1px solid var(--rule); font-size: .92rem; }
.toc-search { width: 100%; font: inherit; font-size: .95rem; padding: .5rem .75rem; margin: .4rem 0 .2rem; border: 1px solid var(--rule); border-radius: 6px; background: var(--panel); color: var(--fg); }
.toc-search:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
.toc-count { font-size: .85rem; color: var(--muted); margin: .2rem 0 0; }
.links { font-size: .92rem; color: var(--muted); }

/* 目录页 */
.toc { list-style: none; padding: 0; margin: .4rem 0 1.2rem; }
.toc li { border-top: 1px solid var(--rule); padding: .55rem 0; margin: 0; }
.toc .num { font-family: var(--mono); font-variant-numeric: tabular-nums; color: var(--muted); font-size: .8rem; margin-right: .6rem; }
.toc .star { color: var(--accent); font-weight: 600; margin-left: .4rem; font-size: .9rem; }

/* Mock 进度（nav.js 的 buildMock，状态在 progress.js） */
.mock h3 { color: var(--muted); font-size: .9rem; margin: 1.1rem 0 .1rem; }
.mock-list li { display: flex; flex-wrap: wrap; align-items: baseline; }
.mock-list .num { min-width: 2.6rem; }
.mock-list a { flex: 1; min-width: 0; }
.mock-list .toc-sub { flex-basis: 100%; margin-left: 3.2rem; }
.st { font-size: .78rem; font-weight: 600; line-height: 1.5; white-space: nowrap; padding: 0 .55rem; margin-left: .6rem; border: 1px solid currentColor; border-radius: 999px; }
.st-ok { color: var(--bg); background: var(--ok); border-color: var(--ok); }
.st-seen { color: var(--c2); background: var(--c2-soft); }
.st-fail { color: var(--accent); background: var(--c1-soft); }
.st-none { color: var(--muted); border-style: dashed; font-weight: 400; }
.mock-sum { margin: 0 0 .5rem; }
.mock-sum .st { margin: 0 .5rem 0 0; }

/* 标签和筛选（nav.js 生成；公司和分类标签是 nav.js 里的 KP，掌握情况在 progress.js） */
.filters { font-family: var(--ui); margin: 1.2rem 0 .6rem; padding: .7rem 1rem .8rem; border: 1px solid var(--rule); border-radius: 10px; background: var(--panel); }
.filters .toc-search, .filters select { background: var(--bg); }
.filters .row { display: flex; flex-wrap: wrap; align-items: center; gap: .4rem .45rem; margin: .45rem 0; }
.filters .lab { font-size: .82rem; font-weight: 600; color: var(--muted); min-width: 2.6rem; }
.filters .toc-search { flex: 1 1 16rem; width: auto; margin: 0; }
.filters select { font: inherit; font-size: .88rem; padding: .45rem .6rem; border: 1px solid var(--rule); border-radius: 6px; background: var(--panel); color: var(--fg); }
.chip { font-family: var(--ui); font-size: .84rem; line-height: 1.4; padding: .3rem .8rem; border: 1px solid var(--rule); border-radius: 999px; background: transparent; color: var(--fg); cursor: pointer; }
.chip:hover { border-color: var(--accent); }
.chip:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
.chip[aria-pressed="true"] { background: var(--accent); border-color: var(--accent); color: var(--bg); }
.chip .n { margin-left: .35rem; font-size: .76rem; color: var(--muted); }
.chip[aria-pressed="true"] .n { color: inherit; opacity: .85; }
.kp-list li { display: flex; flex-wrap: wrap; align-items: baseline; gap: .3rem .45rem; }
.kp-list .num { min-width: 2.5rem; margin-right: 0; }
.kp-list li { padding: .65rem 0; }
.kp-list a.t { flex: 1 1 15rem; min-width: 0; color: var(--fg); text-decoration: none; }
.kp-list a.t:hover { color: var(--accent); text-decoration: underline; }
[data-sort="k"] .kp-list .tg-k { display: none; }
.sec { display: flex; align-items: baseline; gap: .55rem; }
.sec .n { font-family: var(--ui); font-size: .8rem; font-weight: 400; color: var(--muted); font-variant-numeric: tabular-nums; }
.kp-list .star { margin-left: 0; }
.kp-list .st, .kp-tags .st { margin-left: 0; }
.kp-list .toc-sub { flex-basis: 100%; margin: .1rem 0 0 2.95rem; }
.tg { font-family: var(--ui); font-size: .72rem; line-height: 1.4; white-space: nowrap; padding: .12rem .55rem; border: 1px solid var(--rule); border-radius: 999px; color: var(--muted); text-decoration: none; }
.tg-k { color: var(--c2); background: var(--c2-soft); border-color: transparent; }
.tg-asked { color: var(--accent); background: var(--c1-soft); border-color: transparent; }
.tg-prep { color: var(--accent); border-color: currentColor; border-style: dashed; }
.tg-src { color: var(--ok); border-color: currentColor; }
a.tg:hover { border-color: currentColor; border-style: solid; }
.qa .more { font-family: var(--ui); font-size: .85rem; }
.kp-tags { display: flex; flex-wrap: wrap; align-items: center; gap: .35rem .4rem; margin: .3rem 0 .8rem; }
.related { font-family: var(--ui); margin-top: 2.2rem; padding-top: .9rem; border-top: 1px solid var(--rule); font-size: .9rem; line-height: 1.9; }
.related b { display: block; color: var(--muted); font-weight: 600; }
/* inline-block：链接之间没有空白字符，不这样写整行不会折行，同类页面一多就把页面撑出横向滚动 */
.related a { display: inline-block; margin-right: 1rem; }

/* 示意图：inline SVG，颜色全部走主题变量 */
.fig { margin: .8rem 0 1.4rem; }
.fig svg { display: block; width: 100%; max-width: 560px; height: auto; margin: 0 auto; }
.fig figcaption { font-size: .9rem; color: var(--muted); margin-top: .5rem; line-height: 1.6; }
.fig text { font-family: var(--serif); fill: var(--fg); font-size: 13px; }
.fig .m { fill: var(--muted); font-size: 12px; }
.fig .hd { font-weight: 600; font-size: 13px; }
.fig .acc { fill: var(--accent); font-weight: 600; }
.fig .box { fill: var(--panel); stroke: var(--rule); }
.fig .hot { fill: var(--panel); stroke: var(--accent); stroke-width: 1.6; }
.fig .bwd { fill: none; stroke: var(--accent); stroke-width: 1.2; stroke-dasharray: 5 4; }
.fig .stale { fill: none; stroke: var(--rule); stroke-dasharray: 3 3; }
.fig .ln { fill: none; stroke: var(--muted); stroke-width: 1.3; }
.fig .ah { fill: var(--muted); }
.fig .f1 { fill: var(--c1-soft); stroke: var(--accent); }
.fig .f2 { fill: var(--c2-soft); stroke: var(--c2); }
.fig .c2 { fill: var(--c2); font-weight: 600; }
.fig .ln1 { fill: none; stroke: var(--accent); stroke-width: 1.4; }
.fig .ln2 { fill: none; stroke: var(--c2); stroke-width: 1.4; }
.fig .ah1c { fill: var(--accent); }
.fig .ah2c { fill: var(--c2); }
.fig .axis { fill: none; stroke: var(--fg); stroke-width: 1; }
.fig .grid { fill: none; stroke: var(--rule); stroke-width: 1; }

/* 目录页的专题：整段内容折叠在目录页里 */
.track { padding: 0; margin: 0; border: 0; border-bottom: 1px solid var(--rule); border-radius: 0; }
.track:first-of-type { border-top: 1px solid var(--rule); margin-top: 1.5rem; }
.track > summary { position: relative; display: grid; gap: .1rem; padding: .8rem 2.2rem .8rem 0; list-style: none; }
.track > summary::-webkit-details-marker { display: none; }
.track > summary::after { content: ""; position: absolute; right: .4rem; top: 1.25rem; width: .5rem; height: .5rem; border-right: 1.5px solid var(--muted); border-bottom: 1.5px solid var(--muted); transform: rotate(45deg); transition: transform .2s cubic-bezier(.16, 1, .3, 1); }
.track[open] > summary::after { transform: translateY(.25rem) rotate(-135deg); }
.track .tt { font-size: 1.05rem; font-weight: 600; }
.track .td { font-size: .92rem; font-weight: 400; color: var(--muted); }
.track > summary:hover .tt { color: var(--accent); }
.track[open] { padding-bottom: 1.6rem; }
.track p, .track li { font-size: 1rem; }
.part-h { font-size: 1.05rem; margin: 1.8rem 0 .5rem; padding-top: 0; border-top: 0; }
h4 { font-size: .98rem; font-weight: 600; margin: 1.3rem 0 .4rem; }
h4 .code { font-family: var(--mono); font-size: .8rem; font-weight: 400; color: var(--muted); margin-right: .55rem; }
.track + .links { margin-top: .9rem; }
@media (prefers-reduced-motion: reduce) { .track > summary::after { transition: none; } }

/* 课程复习页（cpsc4880.html，由 tools/ml-速查/build_cpsc4880.py 生成）：一题一个可折叠的问答 */
.part-toc { font-family: var(--ui); font-size: .88rem; margin: 1.2rem 0 0; }
.part-toc ul { list-style: none; padding: 0; margin: 0; }
.part-toc li { margin: 0; padding: .45rem 0; border-top: 1px solid var(--rule); line-height: 1.9; }
.part-toc a { display: inline-block; margin-right: .9rem; font-weight: 600; color: var(--fg); text-decoration: none; }
.part-toc a.sub { font-weight: 400; color: var(--muted); }
.part-toc a:hover { color: var(--accent); text-decoration: underline; }
.toolbar { display: flex; flex-wrap: wrap; gap: .45rem; margin: 1.2rem 0 0; }
h3 .code { font-family: var(--mono); font-size: .8rem; font-weight: 400; color: var(--muted); margin-right: .55rem; }
.qa { padding: 0; border-radius: 8px; }
.qa > summary { position: relative; display: flex; flex-wrap: wrap; align-items: baseline; gap: .3rem .6rem; padding: .7rem 2.4rem .7rem 1rem; list-style: none; }
.qa > summary::-webkit-details-marker { display: none; }
.qa > summary::after { content: ""; position: absolute; right: 1.05rem; top: 1.1rem; width: .42rem; height: .42rem; border-right: 1.5px solid var(--muted); border-bottom: 1.5px solid var(--muted); transform: rotate(45deg); transition: transform .2s cubic-bezier(.16, 1, .3, 1); }
.qa[open] > summary::after { transform: translateY(.2rem) rotate(-135deg); }
.qa[open] > summary { margin-bottom: 0; }
.qa .qn { font-family: var(--mono); font-size: .76rem; font-weight: 400; color: var(--muted); font-variant-numeric: tabular-nums; min-width: 2.4rem; }
.qa .qt { flex: 1 1 14rem; min-width: 0; }
.qa .ans { margin: 0; padding: 0 1.1rem .9rem 2.2rem; }
.tg-key { color: var(--bg); background: var(--accent); border-color: transparent; }
.qa-link { display: flex; flex-wrap: wrap; align-items: baseline; gap: .3rem .6rem; margin: .45rem 0; padding: .7rem 1rem; border: 1px dashed var(--rule); border-radius: 8px; font-size: .96rem; font-weight: 600; }
.qa-link .qn { font-family: var(--mono); font-size: .76rem; font-weight: 400; color: var(--muted); font-variant-numeric: tabular-nums; min-width: 2.4rem; }
.qa-link .qt { flex: 1 1 14rem; min-width: 0; }
.only-key .qa:not(.key), .only-key .qa-link:not(.key), .only-key .sub:not(.has-key), .only-key .part:not(.has-key) { display: none; }
@media (prefers-reduced-motion: reduce) { .qa > summary::after { transition: none; } }

/* 速成课（infra-course、infra-l*.html） */
.lead { font-size: 1.02rem; }
.you { border: 1px solid var(--rule); border-radius: 6px; padding: .6rem .9rem; margin: .6rem 0 .9rem; font-size: .95rem; }
.you b { color: var(--accent); margin-right: .4rem; }
.next { background: var(--panel); border-radius: 6px; padding: .7rem 1rem; margin: 1.4rem 0 0; font-size: .95rem; }
.next b { color: var(--accent); margin-right: .4rem; }
.toc .toc-sub { display: block; font-size: .85rem; color: var(--muted); margin-left: 1.9rem; }

/* 手撕代码 */
pre { background: var(--panel); border-radius: 6px; padding: .8rem 1rem; margin: .5rem 0 .6rem; overflow-x: auto; font-size: .8rem; line-height: 1.55; font-variant-ligatures: none; }
pre code { background: none; padding: 0; font-size: inherit; }

/* 来源 */
.src { font-size: .88rem; color: var(--muted); margin-top: 1.6rem; }
.src b { color: var(--fg); font-weight: 600; margin-right: .4rem; }

/* 表格。position: relative 是为了收住格子里公式的隐藏 MathML（KaTeX 把它绝对定位）：
   表格在手机上横向滚动时，右边格子里的 MathML 会跑到视口外，把整页撑出横向滚动 */
table { position: relative; border-collapse: collapse; width: 100%; margin: .6rem 0 1rem; font-size: .92rem; display: block; overflow-x: auto; }
th, td { text-align: left; padding: .4rem .6rem; vertical-align: top; }
thead th { border-bottom: 1px solid var(--fg); font-weight: 600; }
tbody tr + tr td { border-top: 1px solid var(--rule); }
.nw { white-space: nowrap; }

/* 公式 */
/* position: relative 让 KaTeX 里绝对定位的 MathML 也被这个滚动容器收住，否则宽公式在手机上会把整页撑出横向滚动 */
.katex-display { position: relative; overflow-x: auto; overflow-y: hidden; padding: .15rem 0; }
.katex { font-size: 1.04em; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  main { padding-top: 1.6rem; }
  h1 { font-size: 1.45rem; }
}
@media print {
  :root { --bg: #fff; --fg: #000; --panel: #f4f4f4; }
  body { font-size: 10.5pt; line-height: 1.5; }
  main { max-width: none; padding: 0; }
  details { border: 0; padding: 0; }
  a { color: inherit; text-decoration: none; }
}


/* 公开版：不显示个人掌握情况 */
.st { display: none !important; }