/* fonts:start */
/* 自托管字体（tools/fonts.py 生成，别手改）：按全站用到的字符子集化；许可见 assets/fonts/OFL.txt */
@font-face { font-family: "Noto Sans SC"; src: url("/assets/fonts/noto-sans-sc-400.4e940541.woff2") format("woff2"); font-weight: 400; font-style: normal; font-display: swap; unicode-range: U+20-F7, U+394-3C9, U+2012-2074, U+2190-2318, U+2460-25CF, U+2713, U+2E80, U+3000-30FB, U+4E00-7D6E, U+7EA0-8A00, U+8B66-91D1, U+9488-9B54, U+9C9C-9CDE, U+9E1F-9F99, U+FE63-FFE5; }
@font-face { font-family: "Noto Sans SC"; src: url("/assets/fonts/noto-sans-sc-700.7e1a40cb.woff2") format("woff2"); font-weight: 700; font-style: normal; font-display: swap; unicode-range: U+20-F7, U+394-3C9, U+2012-2074, U+2190-2318, U+2460-25CF, U+2713, U+2E80, U+3000-30FB, U+4E00-7D6E, U+7EA0-8A00, U+8B66-91D1, U+9488-9B54, U+9C9C-9CDE, U+9E1F-9F99, U+FE63-FFE5; }
@font-face { font-family: "Noto Serif SC"; src: url("/assets/fonts/noto-serif-sc-600.2ad1b3b9.woff2") format("woff2"); font-weight: 600; font-style: normal; font-display: swap; unicode-range: U+20-F7, U+394-3C9, U+2012-2074, U+2190-2318, U+2460-25CF, U+2713, U+2E80, U+3000-30FB, U+4E00-7D6E, U+7EA0-8A00, U+8B66-91D1, U+9488-9B54, U+9C9C-9CDE, U+9E1F-9FFF, U+FE63-FFE5; }
@font-face { font-family: "JetBrains Mono"; src: url("/assets/fonts/jetbrains-mono-400.f2978443.woff2") format("woff2"); font-weight: 400; font-style: normal; font-display: swap; unicode-range: U+20-7E, U+A0-BD, U+D7-E0, U+F7, U+394-3C9, U+2013-2026, U+2070-2082, U+2190-2197, U+2208-222B, U+2248, U+2260-2265, U+2318, U+2500, U+25B3-25CF; }
@font-face { font-family: "JetBrains Mono"; src: url("/assets/fonts/jetbrains-mono-700.0239070c.woff2") format("woff2"); font-weight: 700; font-style: normal; font-display: swap; unicode-range: U+20-7E, U+A0-BD, U+D7-E0, U+F7, U+394-3C9, U+2013-2026, U+2070-2082, U+2190-2197, U+2208-222B, U+2248, U+2260-2265, U+2318, U+2500, U+25B3-25CF; }
/* fonts:end */

/* 一帧画面是怎么来的 · 站点样式
   视觉方向（DESIGN.md）：冲印暗房与工作台。浅色是冲好的相纸摊在工作台上，深色是关了灯的暗房。
   克制：一种正文字体、一种标题字体、一种数字字体；颜色只有纸、墨、一种蓝（蓝晒）和一种安全灯红（只做小记号）。
   管线八环一环一色：OKLCH 明度一致（浅色 L 0.60 / 深色 L 0.66）、色相等距 45°，
   顺序经过排列使相邻两环在红绿色盲模拟下 ΔE ≥ 8（dataviz 校验器通过），并且每环有自己的形状。 */

/* ------------------------------------------------------------------ tokens */
:root {
  color-scheme: light;
  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --font-mono: "JetBrains Mono", "SF Mono", ui-monospace, Menlo, Consolas, "Noto Sans SC", "PingFang SC", monospace;

  --paper: #f7f5f0;
  --paper-2: #efebe2;
  --card: #fffdf8;
  --ink: #1b1c1f;
  --ink-2: #3b3a36;
  --muted: #5f5b53;
  --line: #ddd7ca;
  --line-2: #c7bfae;
  --accent: #1d4e89;
  --accent-soft: #e3eaf3;
  --safelight: #a53f29;
  --chart-a: #b0541e;          /* 模型 A：只按倍数（虚线） */
  --chart-b: #1d4e89;          /* 模型 B：固定开销 + 倍数（实线） */
  --grid: #e6e1d6;

  /* 管线八环 */
  --st-1: #c25d58;  /* 画面底子  方块 */
  --st-2: #3a84ca;  /* 建模      三角 */
  --st-3: #b25e98;  /* 材质      圆 */
  --st-4: #b17000;  /* 灯光相机  四角星 */
  --st-5: #179765;  /* 渲染      圆环 */
  --st-6: #866ec5;  /* 动画      菱形（关键帧） */
  --st-7: #7e8814;  /* 引擎      六边形 */
  --st-8: #0095a5;  /* 后期      两层 */

  --lk-font: var(--font-sans);
  --lk-mono: var(--font-mono);
  --lk-bg: var(--paper);
  --lk-surface: var(--card);
  --lk-fg: var(--ink);
  --lk-muted: var(--muted);
  --lk-line: var(--line);
  --lk-accent: var(--accent);
  --lk-accent-fg: #ffffff;
  --lk-accent-soft: var(--accent-soft);
  --lk-ok: #1f6a45;
  --lk-ok-soft: #e1efe5;
  --lk-bad: #a3302a;
  --lk-bad-soft: #f7e4e0;
  --lk-warn: #7a5100;
  --lk-warn-soft: #f6ebd2;
  --lk-mark-q: #f6d3c8;
  --lk-mark-k: #f7e7a6;
  --lk-mark-d: #d3e0f2;
  --lk-mark-x: #d8ebcf;
  --lk-radius: 6px;
  --lk-radius-sm: 4px;
  --lk-hit: 44px;
  --lk-gap: 12px;
  --lk-shadow: 0 12px 32px rgb(27 28 31 / 0.14);

  --measure: 680px;
  --wide: 960px;
  --gutter: 16px;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #0f1012;
  --paper-2: #0a0b0c;
  --card: #16181b;
  --ink: #e8e5de;
  --ink-2: #cbc7be;
  --muted: #a39e94;
  --line: #2a2d32;
  --line-2: #3b3f46;
  --accent: #93b4e6;
  --accent-soft: #19243a;
  --safelight: #e56a4f;
  --chart-a: #e38a52;
  --chart-b: #93b4e6;
  --grid: #202328;
  --st-1: #d2736c; --st-2: #5497d9; --st-3: #c274a9; --st-4: #c18434;
  --st-5: #42a878; --st-6: #9882d4; --st-7: #909b3b; --st-8: #00a6b5;
  --lk-accent-fg: #0b1422;
  --lk-ok: #74cf9c; --lk-ok-soft: #13271b;
  --lk-bad: #ff8e7e; --lk-bad-soft: #36170f;
  --lk-warn: #e9bf5f; --lk-warn-soft: #2e230c;
  --lk-mark-q: #5a2c22; --lk-mark-k: #4f4418; --lk-mark-d: #22375a; --lk-mark-x: #27432a;
  --lk-shadow: 0 12px 32px rgb(0 0 0 / 0.55);
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --paper: #0f1012;
    --paper-2: #0a0b0c;
    --card: #16181b;
    --ink: #e8e5de;
    --ink-2: #cbc7be;
    --muted: #a39e94;
    --line: #2a2d32;
    --line-2: #3b3f46;
    --accent: #93b4e6;
    --accent-soft: #19243a;
    --safelight: #e56a4f;
    --chart-a: #e38a52;
    --chart-b: #93b4e6;
    --grid: #202328;
    --st-1: #d2736c; --st-2: #5497d9; --st-3: #c274a9; --st-4: #c18434;
    --st-5: #42a878; --st-6: #9882d4; --st-7: #909b3b; --st-8: #00a6b5;
    --lk-accent-fg: #0b1422;
    --lk-ok: #74cf9c; --lk-ok-soft: #13271b;
    --lk-bad: #ff8e7e; --lk-bad-soft: #36170f;
    --lk-warn: #e9bf5f; --lk-warn-soft: #2e230c;
    --lk-mark-q: #5a2c22; --lk-mark-k: #4f4418; --lk-mark-d: #22375a; --lk-mark-x: #27432a;
    --lk-shadow: 0 12px 32px rgb(0 0 0 / 0.55);
  }
}

/* ------------------------------------------------------------------ base */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font-family: var(--font-sans); font-size: 17px; line-height: 1.8; letter-spacing: 0.01em;
  font-feature-settings: "palt" 0; -webkit-font-smoothing: antialiased;
  padding-bottom: var(--lk-tour-bar-h, 0px);
}
img, svg { max-width: 100%; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 2px; }
h1, h2, h3 { font-family: var(--font-serif); font-weight: 600; line-height: 1.35; letter-spacing: 0.02em; color: var(--ink); }
h1 { font-size: clamp(30px, 5.2vw, 44px); margin: 0 0 12px; }
h2 { font-size: clamp(22px, 3.2vw, 27px); margin: 64px 0 16px; }
h3 { font-size: 19px; margin: 36px 0 10px; }
p { margin: 0 0 1.05em; }
strong { font-weight: 700; }
.num, .mono { font-family: var(--font-mono); font-size: 0.92em; font-variant-numeric: tabular-nums; letter-spacing: 0; }
.muted { color: var(--muted); }
.skip { position: absolute; left: -9999px; top: 8px; }
.skip:focus { left: 8px; z-index: 50; background: var(--card); padding: 8px 12px; }
hr { border: 0; border-top: 1px solid var(--line); margin: 48px 0; }

/* ------------------------------------------------------------------ header */
.site-head {
  position: sticky; top: 0; z-index: 30;
  background: color-mix(in srgb, var(--paper) 92%, transparent);
  -webkit-backdrop-filter: saturate(1.2) blur(10px); backdrop-filter: saturate(1.2) blur(10px);
  border-bottom: 1px solid var(--line);
}
.site-head-in { max-width: 1160px; margin: 0 auto; padding: 0 var(--gutter); display: flex; align-items: center; gap: 8px; min-height: 56px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-family: var(--font-serif); font-weight: 600; font-size: 16px; letter-spacing: 0.04em; min-height: 44px; margin-right: auto; white-space: nowrap; }
.brand-mark { width: 22px; height: 16px; flex: none; }
.brand-mark rect { fill: none; stroke: var(--ink); stroke-width: 1.4; }
.brand-mark circle { fill: var(--safelight); }
.nav { display: flex; align-items: center; gap: 2px; }
.nav a, .theme-btn {
  display: inline-flex; align-items: center; gap: 6px; min-height: 44px; padding: 0 10px; border-radius: 4px;
  color: var(--ink-2); text-decoration: none; font-size: 15px; white-space: nowrap; background: none; border: 0; font-family: inherit; cursor: pointer;
}
.nav a:hover, .theme-btn:hover { color: var(--ink); background: var(--paper-2); }
.nav a[aria-current="page"] { color: var(--ink); box-shadow: inset 0 -2px 0 var(--ink); border-radius: 0; }
.due-badge { font-family: var(--font-mono); font-size: 12px; min-width: 20px; height: 20px; padding: 0 6px; border-radius: 10px; background: var(--safelight); color: #fff; display: inline-grid; place-items: center; }
:root[data-theme="dark"] .due-badge { color: #140a07; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .due-badge { color: #140a07; } }
.due-badge[hidden] { display: none; }
.theme-btn svg { width: 18px; height: 18px; }
.theme-btn svg * { fill: none; stroke: currentColor; stroke-width: 1.6; }
@media (max-width: 560px) {
  .brand-text { display: none; }
  .nav a { padding: 0 8px; font-size: 14.5px; }
  .theme-btn { padding: 0 8px; }
}

/* ------------------------------------------------------------------ page frame */
.wrap { max-width: 1160px; margin: 0 auto; padding: 0 var(--gutter); }
.article {
  display: grid;
  grid-template-columns:
    [full-start] minmax(var(--gutter), 1fr)
    [wide-start] minmax(0, calc((var(--wide) - var(--measure)) / 2))
    [text-start] minmax(0, var(--measure)) [text-end]
    minmax(0, calc((var(--wide) - var(--measure)) / 2)) [wide-end]
    minmax(var(--gutter), 1fr) [full-end];
}
.article > * { grid-column: text; min-width: 0; }
.article > .wide { grid-column: wide; }
.article > .full { grid-column: full; }
@media (max-width: 1000px) {
  /* 放不下 960 的出血栏时，正文、宽块都铺满两侧留白之间（不让空栏抢正文的宽度） */
  .article { grid-template-columns: [full-start] var(--gutter) [wide-start text-start] minmax(0, 1fr) [text-end wide-end] var(--gutter) [full-end]; }
}

/* 旁注：宽屏放页边，窄屏折进正文 */
.with-note { position: relative; }
.note {
  font-size: 14px; line-height: 1.65; color: var(--muted);
  border-left: 2px solid var(--line-2); padding: 2px 0 2px 12px; margin: -4px 0 20px;
}
.note b { color: var(--ink-2); font-weight: 600; }
@media (min-width: 1240px) {
  .with-note > .note { position: absolute; top: 4px; left: calc(100% + 44px); width: 216px; margin: 0; }
}

/* 案例号、环节 */
.case { font-family: var(--font-mono); font-size: 0.8em; letter-spacing: 0; color: var(--muted); white-space: nowrap; }
.stage { display: inline-flex; align-items: center; gap: 0.38em; white-space: nowrap; }
.stage::before { content: ""; flex: none; width: 0.72em; height: 0.72em; background: var(--c, var(--ink)); }
.stage[data-s="1"] { --c: var(--st-1); } .stage[data-s="2"] { --c: var(--st-2); } .stage[data-s="3"] { --c: var(--st-3); } .stage[data-s="4"] { --c: var(--st-4); }
.stage[data-s="5"] { --c: var(--st-5); } .stage[data-s="6"] { --c: var(--st-6); } .stage[data-s="7"] { --c: var(--st-7); } .stage[data-s="8"] { --c: var(--st-8); }
.stage[data-s="2"]::before { clip-path: polygon(50% 4%, 100% 96%, 0 96%); }
.stage[data-s="3"]::before { border-radius: 50%; }
.stage[data-s="4"]::before { clip-path: polygon(50% 0, 62% 38%, 100% 50%, 62% 62%, 50% 100%, 38% 62%, 0 50%, 38% 38%); width: 0.86em; height: 0.86em; }
.stage[data-s="5"]::before { background: transparent; border-radius: 50%; box-shadow: inset 0 0 0 0.16em var(--c); }
.stage[data-s="6"]::before { clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%); width: 0.8em; height: 0.8em; }
.stage[data-s="7"]::before { clip-path: polygon(25% 6%, 75% 6%, 100% 50%, 75% 94%, 25% 94%, 0 50%); }
.stage[data-s="8"]::before { background: linear-gradient(var(--c) 0 0) top / 100% 38% no-repeat, linear-gradient(var(--c) 0 0) bottom / 100% 38% no-repeat; }

/* ------------------------------------------------------------------ lesson head */
.lesson-head { padding: 44px 0 8px; }
.kicker { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 14px; font-size: 14px; color: var(--muted); margin: 0 0 14px; }
.kicker .edge { font-family: var(--font-mono); letter-spacing: 0.08em; color: var(--safelight); font-size: 13px; }
.lede { font-size: 19px; line-height: 1.85; color: var(--ink); }
.meta-row { display: flex; flex-wrap: wrap; gap: 8px 18px; font-size: 14px; color: var(--muted); margin: 18px 0 0; padding: 12px 0 0; border-top: 1px solid var(--line); }
.sec-no { display: block; font-family: var(--font-mono); font-size: 12.5px; letter-spacing: 0.12em; color: var(--safelight); margin-bottom: 4px; font-weight: 400; }

/* 公式、算式 */
.calc { font-family: var(--font-mono); font-size: 15.5px; line-height: 1.7; background: var(--paper-2); border-left: 2px solid var(--ink); padding: 12px 16px; margin: 4px 0 22px; overflow-x: auto; letter-spacing: 0; }
.calc .res { font-weight: 700; white-space: nowrap; }
.calc .dim { color: var(--muted); font-size: 0.9em; }
.calc sub { font-size: 0.72em; }

/* 小表 */
.tbl-wrap { overflow-x: auto; margin: 6px 0 22px; }
table.data { border-collapse: collapse; width: 100%; font-size: 15px; line-height: 1.5; }
table.data caption { text-align: left; font-size: 13.5px; color: var(--muted); padding-bottom: 8px; caption-side: top; }
table.data th, table.data td { padding: 8px 10px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: baseline; }
table.data thead th { font-weight: 600; font-size: 13px; color: var(--muted); border-bottom: 1px solid var(--line-2); white-space: nowrap; }
table.data td.n, table.data th.n { text-align: right; font-family: var(--font-mono); font-variant-numeric: tabular-nums; font-size: 14px; letter-spacing: 0; white-space: nowrap; }
table.data tr.hl td { background: var(--accent-soft); }

/* ------------------------------------------------------------------ figures: 裁切标记 */
.print { position: relative; margin: 28px 0 30px; }
.print img { display: block; width: 100%; height: auto; background: var(--paper-2); }
/* 本站的图都铺满栏宽，图块直接占满（运行库默认按 img 的 width 属性预留图块宽度，比栏窄的图会窄一截；高度都按 width/height 的比例预留，懒加载不挪页面）。 */
figure.lk-fig { width: auto; }
.print::before, .print::after { content: ""; position: absolute; width: 14px; height: 14px; border-color: var(--line-2); border-style: solid; pointer-events: none; }
.print::before { top: -9px; left: -9px; border-width: 1px 0 0 1px; }
.print::after { bottom: -9px; right: -9px; border-width: 0 1px 1px 0; }
figcaption { font-size: 14px; line-height: 1.65; color: var(--muted); margin-top: 12px; }
figcaption b { color: var(--ink-2); font-weight: 600; }

/* 并排的两张真帧 + 下面一句图注（第 3、4 课等） */
.pair-wrap { margin: 28px 0 30px; }
.pair-cap { font-size: 14px; line-height: 1.65; color: var(--muted); margin: 12px 0 0; }
.pair-cap b { color: var(--ink-2); font-weight: 600; }
.do-link { font-size: 14.5px; }
figure picture { display: block; }

/* 一排三格的真帧（第 5、12 课） */
.strip { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; margin: 20px 0 16px; }
.strip > div { min-width: 0; }
.strip img { display: block; width: 100%; height: auto; background: #050506; }
.strip span { display: block; margin-top: 6px; font-size: 13px; line-height: 1.5; color: var(--muted); font-family: var(--font-mono); letter-spacing: 0; }
.strip span b { display: block; color: var(--ink); font-weight: 600; }
.strip figcaption { grid-column: 1 / -1; margin-top: 2px; }

/* 代码：行内与成块 */
code { font-family: var(--font-mono); font-size: 0.88em; letter-spacing: 0; background: var(--paper-2); padding: 1px 4px; border-radius: 3px; overflow-wrap: anywhere; }
pre.code { margin: 6px 0 20px; padding: 12px 16px; background: var(--paper-2); border-left: 2px solid var(--st-4); overflow-x: auto; font-size: 13.5px; line-height: 1.65; }
pre.code code { background: none; padding: 0; font-size: inherit; white-space: pre; overflow-wrap: normal; }

/* 代码画的示意图（.fig-svg）：字和线都走主题色 */
.fig-svg { margin: 22px 0 26px; }
.fig-svg svg { display: block; width: 100%; max-width: 560px; height: auto; margin: 0 auto; overflow: visible; font-family: var(--font-sans); }
.fig-svg text { fill: var(--ink); }
.fig-svg .f-title { font-family: var(--font-serif); font-weight: 600; font-size: 14px; }
.fig-svg .f-small { font-size: 12.5px; fill: var(--muted); }
.fig-svg .f-lab { font-family: var(--font-mono); font-size: 13.5px; letter-spacing: 0; }
.fig-svg .f-grid { stroke: var(--grid); stroke-width: 1; fill: none; }
.fig-svg .f-axis { stroke: var(--line-2); stroke-width: 1.5; fill: none; }
.fig-svg .f-origin { fill: var(--ink); }
.fig-svg .f-ghost { fill: none; stroke: var(--muted); stroke-width: 1.2; stroke-dasharray: 3 2; }
.fig-svg .f-obj { fill: var(--st-4); stroke: var(--ink); stroke-width: 1; }
.fig-svg .f-move, .fig-svg .f-arc { fill: none; stroke: var(--safelight); stroke-width: 1.6; stroke-dasharray: 5 3; }
.fig-svg .f-move-head { fill: none; stroke: var(--safelight); stroke-width: 1.6; }
.fig-svg .f-plane { stroke: var(--ink); stroke-width: 2; }
.fig-svg .f-post { stroke: var(--st-4); stroke-width: 5; stroke-linecap: round; }
.fig-svg .f-ray { stroke: var(--muted); stroke-width: 1; stroke-dasharray: 4 3; }
.fig-svg .f-hit, .fig-svg .f-hit2 { stroke: var(--st-4); stroke-width: 4; }
.fig-svg .f-dim { stroke: var(--muted); stroke-width: 1; fill: none; }
.fig-svg .f-halo { paint-order: stroke; stroke: var(--card); stroke-width: 4px; stroke-linejoin: round; }
.fig-svg figcaption { max-width: var(--measure); margin-left: auto; margin-right: auto; }

/* ------------------------------------------------------------------ 实验台（lab） */
.bench { margin: 26px 0 8px; background: var(--card); border: 1px solid var(--line); border-radius: 6px; }
.bench-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; padding: 12px 18px 10px; border-bottom: 1px solid var(--line); }
.bench-tag { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.1em; color: var(--safelight); }
.bench-title { font-family: var(--font-serif); font-weight: 600; font-size: 17px; }
.bench [data-lk="lab"] { padding: 14px 18px 16px; }
.lab-readout { font-size: 15px; line-height: 1.7; margin: 10px 0 4px; min-height: 3.4em; }
.lab-readout .big { font-family: var(--font-mono); font-size: 22px; font-weight: 600; letter-spacing: 0; }
.lab-readout .tag { font-size: 13px; color: var(--muted); }
.lab-groups { display: grid; gap: 6px 28px; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); margin-top: 14px; }
.lab-group { border: 0; margin: 0; padding: 8px 0 0; border-top: 1px solid var(--line); min-width: 0; }
.lab-group legend { font-size: 12.5px; letter-spacing: 0.06em; color: var(--muted); padding: 0 8px 0 0; }
.lab-group .lk-ctl { display: grid; grid-template-columns: 5.4em minmax(0, 1fr) auto; align-items: center; gap: 4px 10px; width: 100%; }
.lab-group .lk-ctl-toggle { grid-template-columns: auto minmax(0, 1fr); }
.lab-group .lk-ctl-label { font-size: 14.5px; color: var(--ink-2); }
.lab-group .lk-ctl input[type="range"] { width: 100%; min-width: 0; }
.lab-group .lk-ctl select { width: 100%; grid-column: 2 / 4; }
.lab-group select { min-height: 40px; padding: 6px 10px; border: 1px solid var(--line-2); border-radius: 4px; background: var(--card); color: var(--ink); font: inherit; font-size: 15px; max-width: 100%; }
.lk-ctl-out { font-family: var(--font-mono); font-size: 14px; color: var(--ink-2); min-width: 4.5em; }
.chart { display: block; width: 100%; height: auto; overflow: visible; font-family: var(--font-sans); }
.chart text { fill: var(--muted); font-size: 12.5px; }
.chart .t-ink { fill: var(--ink); }
.chart .t-strong { fill: var(--ink); font-weight: 600; }
.chart .t-mono { font-family: var(--font-mono); letter-spacing: 0; }
.chart .grid line { stroke: var(--grid); stroke-width: 1; }
.chart .axis { stroke: var(--line-2); stroke-width: 1; fill: none; }
.chart .m-a { stroke: var(--chart-a); stroke-width: 2; fill: none; stroke-dasharray: 7 5; }
.chart .m-b { stroke: var(--chart-b); stroke-width: 2; fill: none; }
.chart .m-a-fill { fill: var(--chart-a); }
.chart .m-b-fill { fill: var(--chart-b); }
.chart .t-a { fill: var(--chart-a); font-weight: 600; }
.chart .t-b { fill: var(--chart-b); font-weight: 600; }
.chart .pt { fill: var(--ink); stroke: var(--card); stroke-width: 2; }
.chart .pt-cur { fill: none; stroke: var(--ink); stroke-width: 1.5; }
.chart .cur-line { stroke: var(--ink); stroke-width: 1; stroke-dasharray: 2 3; opacity: 0.6; }
.chart .extrap { fill: var(--paper-2); }
.chart .res-a { fill: var(--chart-a); }
.chart .res-b { fill: var(--chart-b); }
.chart .zero { stroke: var(--line-2); stroke-width: 1; }
.chart .lead { stroke: var(--muted); stroke-width: 1; }
.chart .t-halo { paint-order: stroke; stroke: var(--card); stroke-width: 4px; stroke-linejoin: round; }
.chart .slot { fill: var(--paper-2); }
.chart .slot-line { stroke: var(--line-2); stroke-width: 1; }
.chart .work { fill: var(--st-5); }
.chart .wait { fill: url(#hatch); }
.chart .hatch-line { stroke: var(--line-2); stroke-width: 1.2; }
.chart .over { fill: var(--safelight); }
.chart .budget { stroke: var(--ink); stroke-width: 1.5; }
.chart .gb-free { fill: var(--paper-2); stroke: var(--line-2); stroke-width: 1; }
.chart .gb-job { fill: color-mix(in srgb, var(--st-5) 26%, var(--card)); stroke: var(--st-5); stroke-width: 1.5; }
.chart .gb-job-2 { fill: color-mix(in srgb, var(--st-6) 26%, var(--card)); stroke: var(--st-6); stroke-width: 1.5; }
.chart .gb-sys { fill: var(--line-2); }
.chart .gb-page { fill: url(#hatch2); }
.chart .hatch2-line { stroke: var(--safelight); stroke-width: 1.4; }
.chart .cap { stroke: var(--ink); stroke-width: 2; }
.chart .bar-a { fill: var(--st-5); }
.chart .bar-b { fill: var(--st-6); }

/* 诚实声明（紧跟在实验台下面时贴近一点） */
.honesty { margin: 14px 0 34px; padding: 12px 0 0; border-top: 1px dashed var(--line-2); font-size: 14px; line-height: 1.7; color: var(--muted); display: grid; grid-template-columns: max-content 1fr; gap: 4px 14px; }
.honesty dt { color: var(--ink-2); font-weight: 600; }
.honesty dd { margin: 0; }
.article > .bench + .honesty { margin-top: 12px; }
[data-lk="predict"] .bench + .honesty { margin-bottom: 4px; }
@media (max-width: 520px) {
  .honesty { grid-template-columns: 1fr; } .honesty dd { margin-bottom: 6px; }
  [data-lk="predict"] { padding: 16px 14px 14px; }
  .bench [data-lk="lab"] { padding: 12px 12px 14px; }
  .bench-head { padding: 10px 12px 8px; }
  [data-lk="predict"] .bench { margin-left: -6px; margin-right: -6px; }
}

/* ------------------------------------------------------------------ lk 原件的本站样式 */
.lk-card { border-radius: 6px; box-shadow: none; }
[data-lk="predict"] {
  margin: 30px 0 26px; padding: 18px 20px 16px; background: var(--card);
  border: 1px solid var(--line); border-top: 3px solid var(--ink); border-radius: 0 0 6px 6px;
}
[data-lk="predict"].wide > *, [data-lk="predict"].wide > [data-part="reveal"] > * { max-width: var(--measure); margin-left: auto; margin-right: auto; }
[data-lk="predict"].wide > [data-part="reveal"] { max-width: none; }
[data-lk="predict"].wide > [data-part="reveal"] > .bench { max-width: none; }
[data-lk="predict"] > [data-part="q"] { font-family: var(--font-serif); font-weight: 600; font-size: 18.5px; line-height: 1.6; margin-block: 0 14px; }
[data-lk="predict"] > [data-part="q"]::before { content: "先猜"; display: block; font-family: var(--font-mono); font-weight: 400; font-size: 12px; letter-spacing: 0.14em; color: var(--safelight); margin-bottom: 6px; }
[data-lk="predict"] > [data-part="reveal"] { margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--line); }
[data-lk="predict"] > [data-part="reveal"] > :last-child { margin-bottom: 0; }
.lk-predict-opt { border-radius: 4px; }
[data-lk="checkpoint"] { margin: 26px 0 18px; padding: 14px 18px; border-left: 3px solid var(--st-5); background: var(--paper-2); border-radius: 0 6px 6px 0; }
[data-lk="checkpoint"] > p:first-child { font-weight: 600; }
[data-lk="mq"] { margin: 18px 0; }
.lk-mq.lk-card { border-left: 3px solid var(--line-2); }
.lk-mq-stem { font-size: 16.5px; }
.lk-opt, .lk-predict-opt, .lk-btn, .lk-input, .lk-ta { border-radius: 4px; }
.lk-stat { border-radius: 6px; }
.lk-stat-v { font-family: var(--font-mono); letter-spacing: 0; }
.lk-unitnav-link { border-radius: 6px; }
.lk-h { font-family: var(--font-serif); }
.lk-badge { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0; }

/* 导览入口 */
.tour-slot { margin: 24px 0 30px; padding: 16px 18px; border: 1px solid var(--line); border-radius: 6px; background: var(--paper-2); }
.tour-slot > p { margin: 0 0 10px; font-size: 15px; color: var(--muted); }

/* 课末 */
.coda { margin-top: 56px; padding-top: 22px; border-top: 3px double var(--line-2); }
details.walls { margin: 18px 0 8px; border: 1px solid var(--line); border-radius: 6px; background: var(--card); }
details.walls > summary { min-height: 44px; display: flex; align-items: center; padding: 0 16px; cursor: pointer; font-weight: 600; }
details.walls > div { padding: 0 18px 12px; }

/* ------------------------------------------------------------------ 首页 */
.home-hero { padding: 40px 0 24px; }
.home-hero h1 { font-size: clamp(34px, 6.4vw, 60px); letter-spacing: 0.06em; margin-bottom: 14px; }
.home-hero .sub { font-size: clamp(17px, 2.2vw, 20px); color: var(--ink-2); max-width: 36em; margin: 0 0 26px; }
.stage-cap { font-size: 13.5px; color: var(--muted); margin: 12px 0 0; line-height: 1.65; }
@media (min-width: 900px) { .stage-cap { max-width: 60em; } }

.cta-row { display: flex; flex-wrap: wrap; gap: 10px 12px; align-items: center; margin: 34px 0 0; }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 48px; padding: 0 22px; border-radius: 4px; font-size: 16px; font-weight: 600; text-decoration: none; border: 1px solid var(--ink); color: var(--ink); background: transparent; font-family: inherit; }
.btn:hover { background: var(--paper-2); text-decoration: none; }
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-primary:hover { background: var(--ink-2); color: var(--paper); }
.btn[aria-disabled="true"] { opacity: 0.5; pointer-events: none; }
.cta-note { width: 100%; font-size: 14px; color: var(--muted); margin: 2px 0 0; }

.promise { margin: 60px 0 0; display: grid; gap: 0; border-top: 1px solid var(--ink); }
.promise h2 { margin: 18px 0 8px; font-size: 15px; font-family: var(--font-sans); font-weight: 600; letter-spacing: 0.1em; color: var(--muted); }
.promise ol { list-style: none; margin: 0; padding: 0; counter-reset: pr; display: grid; gap: 0; }
.promise li { counter-increment: pr; display: grid; grid-template-columns: 3.2em 1fr; align-content: start; gap: 12px; padding: 18px 0; border-bottom: 1px solid var(--line); }
.promise li::before { content: "0" counter(pr); font-family: var(--font-mono); color: var(--safelight); font-size: 14px; padding-top: 5px; letter-spacing: 0.08em; }
.promise .can { font-family: var(--font-serif); font-size: 20px; font-weight: 600; line-height: 1.5; display: block; }
.promise .eg { display: block; font-size: 15px; color: var(--muted); margin-top: 4px; }
@media (min-width: 900px) {
  .promise ol { grid-template-columns: repeat(3, 1fr); gap: 0 32px; }
  .promise li { grid-template-columns: 1fr; gap: 6px; border-bottom: 0; }
}

.map-sec { margin: 72px 0 0; }
.map-sec > h2 { margin-top: 0; }
.map-lede { color: var(--ink-2); max-width: 40em; }
.pipeline { margin: 24px 0 8px; }
.pipeline svg { display: block; width: 100%; height: auto; overflow: visible; }
.pipeline svg text { fill: var(--ink); font-family: var(--font-sans); }
.pipeline .rail { stroke: var(--line-2); stroke-width: 2; fill: none; }
.pipeline .node-bg { fill: var(--card); stroke: var(--line); stroke-width: 1; }
.pipeline .node-name { font-size: 15px; font-weight: 600; font-family: var(--font-serif); }
.pipeline .node-units { font-size: 12px; fill: var(--muted) !important; font-family: var(--font-mono); }
.pipeline .node-no { font-size: 11px; fill: var(--muted) !important; font-family: var(--font-mono); letter-spacing: 0.1em; }
.pipeline .pin-line { stroke: var(--line-2); stroke-width: 1; }
.pipeline .pin { cursor: pointer; }
.pipeline .pin rect { fill: var(--paper); stroke: var(--ink); stroke-width: 1; }
.pipeline .pin text { font-size: 11.5px; font-family: var(--font-mono); fill: var(--ink); }
.pipeline .pin:hover rect, .pipeline .pin:focus rect, .pipeline .pin[aria-pressed="true"] rect { fill: var(--ink); }
.pipeline .pin:hover text, .pipeline .pin:focus text, .pipeline .pin[aria-pressed="true"] text { fill: var(--paper); }
.pipeline .pin:focus { outline: none; }
.pipeline .pin:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
.pipeline .pin:focus-visible rect { stroke: var(--accent); stroke-width: 2; }
.pins { list-style: none; margin: 18px 0 0; padding: 0; display: grid; gap: 0; grid-template-columns: repeat(auto-fit, minmax(290px, 1fr)); border-top: 1px solid var(--line); }
.pins li { padding: 12px 14px 12px 0; border-bottom: 1px solid var(--line); font-size: 15px; line-height: 1.6; scroll-margin-top: 90px; }
.pins li.on { background: var(--accent-soft); }
.pins .case { margin-right: 8px; }
.pins .where { display: block; font-size: 13px; color: var(--muted); margin-top: 3px; }

.course { margin: 72px 0 0; }
.course > h2 { margin-top: 0; }
.course > p { max-width: 44em; }
.units { list-style: none; margin: 18px 0 0; padding: 0; border-top: 1px solid var(--ink); }
.units li { display: grid; grid-template-columns: 3em 1fr auto; gap: 4px 12px; align-items: baseline; padding: 12px 0; border-bottom: 1px solid var(--line); }
.units .no { font-family: var(--font-mono); font-size: 13px; color: var(--muted); letter-spacing: 0.06em; }
.units .t { font-size: 16.5px; line-height: 1.5; }
.units .t a { color: var(--ink); font-weight: 600; text-decoration: none; box-shadow: inset 0 -2px 0 var(--accent); }
.units .t a:hover { box-shadow: inset 0 -3px 0 var(--accent); }
.units .t .soon { color: var(--muted); }
.units .sm { grid-column: 2 / 3; display: flex; flex-wrap: wrap; gap: 2px 12px; font-size: 13px; color: var(--muted); }
.units .min { font-family: var(--font-mono); font-size: 13px; color: var(--muted); white-space: nowrap; }
.units .core { font-size: 12px; border: 1px solid var(--line-2); border-radius: 3px; padding: 0 6px; color: var(--ink-2); }
.units li.live { background: linear-gradient(90deg, var(--accent-soft), transparent 70%); }

.why-guess { margin: 72px 0 0; padding: 22px 24px; background: var(--paper-2); border-radius: 6px; }
.why-guess h2 { margin: 0 0 8px; font-size: 19px; }
.why-guess p { margin: 0 0 8px; color: var(--ink-2); font-size: 15.5px; }

.site-foot { margin-top: 96px; border-top: 1px solid var(--line); padding: 26px 0 44px; font-size: 13.5px; line-height: 1.75; color: var(--muted); }
.site-foot .row { display: flex; flex-wrap: wrap; gap: 6px 22px; }
.site-foot p { margin: 0 0 8px; }

/* ------------------------------------------------------------------ 复习 / 进度 / 笔记 / 诊断 页 */
.tool-head { padding: 40px 0 6px; }
.tool-head h1 { margin-bottom: 8px; }
.tool-head p { color: var(--ink-2); max-width: 38em; }
.tool-body { margin: 18px 0 0; }
.tool-body .lk-stat { background: var(--card); }
.tool-aside { margin: 40px 0 0; padding-top: 16px; border-top: 1px solid var(--line); font-size: 14.5px; color: var(--muted); }

/* ------------------------------------------------------------------ 打印、截图、减少动效 */
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; transition: none !important; animation: none !important; } }
html[data-lk-shot] .site-head { position: static; }
@media print { .site-head, .cta-row, .tour-slot, .theme-btn { display: none !important; } body { background: #fff; } }