@charset "utf-8";
/* =========================================================================
   Ways to Robot —— 全站样式
   -------------------------------------------------------------------------
   设计系统：Bauhaus（构成主义 / 几何现代主义）
   设计契约（不要随意破坏）：
     1. 颜色：五个令牌，不再增加。
          红  --bh-red     #D02020   强调、状态、几何形
          蓝  --bh-blue    #1040C0   结构、标题、链接、导航
          黄  --bh-yellow  #F0C020   高亮、标记、提示
          黑  --bh-black   #121212   文字、边框、页脚
          米白 --bh-canvas #F0F0F0   画布
        用色纪律：**大面积只用黑白灰，三原色只出现在结构与点缀上**——
        这是「Bauhaus 的骨 + 长文可读性」的折中。整块纯色只出现在
        页脚、表头、徽标、几何装饰这类小面积处。
     2. 字体：正文宋体（长中文最耐读），标题用系统几何无衬线（黑体族）。
        零外部字体请求——站点保持「可离线双击打开」。
     3. 形状：只有两种圆角——0（方）与 999px（圆）。没有中间值。
     4. 深度：一律硬偏移阴影（无模糊）。大结构 8px，组件 4px，微件 3px。
     5. 汉字没有大小写：text-transform:uppercase 只作用于英文标签；
        中文标题用微弱**正**字距，绝不用负字距（会挤字）。
     6. 可达性：红底白字 ≈5.4:1（只配大字号/加粗）；黄底黑字 ≈11:1；
        蓝底白字 ≈8:1；**永不用黄底白字**。焦点态一律 3px 蓝描边。
   ========================================================================= */

:root {
  /* ---------------------------------------------------------- 1. 五色令牌 */
  --bh-red: #d02020;
  --bh-blue: #1040c0;
  --bh-yellow: #f0c020;
  --bh-black: #121212;
  --bh-canvas: #f0f0f0;
  --bh-white: #ffffff;

  /* 同色透明变体（仍是这五个颜色，未引入新色） */
  --bh-black-70: rgba(18, 18, 18, 0.7);
  --bh-black-55: rgba(18, 18, 18, 0.55);
  --bh-black-38: rgba(18, 18, 18, 0.38);
  --bh-black-16: rgba(18, 18, 18, 0.16);
  --bh-black-08: rgba(18, 18, 18, 0.08);
  --bh-blue-10: rgba(16, 64, 192, 0.1);
  --bh-blue-06: rgba(16, 64, 192, 0.06);
  --bh-red-10: rgba(208, 32, 32, 0.1);
  --bh-yellow-tint: #fdf3d0;

  /* ------------------------------------- 2. 语义别名（兼容既有 74 个类） */
  --paper: var(--bh-canvas);
  --ink: var(--bh-black);
  --brand: var(--bh-blue);      /* 旧「墨青」→ 蓝：结构色 */
  --accent: var(--bh-red);      /* 旧「赭石」→ 红：强调色 */
  --ink-70: var(--bh-black-70);
  --ink-55: var(--bh-black-55);
  --ink-38: var(--bh-black-38);
  --brand-12: var(--bh-black-16);
  --brand-08: var(--bh-black-08);
  --brand-05: var(--bh-blue-06);
  --accent-12: var(--bh-red-10);
  --accent-06: var(--bh-blue-06);

  /* ------------------------------------------------------------- 3. 字体 */
  --serif: "宋体", SimSun, "Songti SC", "Noto Serif CJK SC", "Source Han Serif SC",
    "Times New Roman", serif;
  --display: "Arial Black", "Segoe UI Black", "Helvetica Neue", Helvetica, Arial,
    "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  --mono: "JetBrains Mono", "Cascadia Mono", Consolas, "Courier New", monospace;

  /* ------------------------------------------------------- 4. 几何与深度 */
  --bw: 4px;            /* 大结构边框 */
  --bw-sm: 2px;         /* 组件边框 */
  --shadow-lg: 8px 8px 0 0 var(--bh-black);
  --shadow-md: 4px 4px 0 0 var(--bh-black);
  --shadow-sm: 3px 3px 0 0 var(--bh-black);
  --r-square: 0px;
  --r-round: 999px;

  --measure: 42em;
  --pad: 24px;
  --radius: var(--r-square);   /* 兼容旧变量名 */
}

* { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bh-canvas);
  color: var(--bh-black);
  font-family: var(--serif);
  font-size: 17.5px;
  line-height: 1.95;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--bh-yellow); color: var(--bh-black); }

/* 键盘焦点：统一 3px 蓝描边（可达性底线，不要删） */
:focus-visible { outline: 3px solid var(--bh-blue); outline-offset: 2px; }

/* 顶部阅读进度条 —— 一根红色标尺 */
#readbar {
  position: fixed;
  inset: 0 auto auto 0;
  height: 4px;
  width: 0;
  background: var(--bh-red);
  z-index: 60;
  transition: width 0.08s linear;
}

/* ------------------------------------------------------------- 几何元件 */
/* 圆 / 方 / 三角：所有装饰都从这三个形状派生 */
.shape,
.brand__mark i { display: inline-block; }
.shape--circle { border-radius: var(--r-round); }
.shape--square { border-radius: var(--r-square); }
.shape--triangle {
  background: transparent !important;
  width: 0 !important;
  height: 0 !important;
  border-left: 0.5em solid transparent;
  border-right: 0.5em solid transparent;
  border-bottom: 0.86em solid var(--bh-black);
}
.shape--red { background: var(--bh-red); }
.shape--blue { background: var(--bh-blue); }
.shape--yellow { background: var(--bh-yellow); }
.shape--rot { transform: rotate(45deg); }
.shape--outline {
  background: transparent !important;
  border: var(--bw-sm) solid var(--bh-black);
}

/* ------------------------------------------------------------------ 页头 */
.site-head {
  background: var(--bh-white);
  border-bottom: var(--bw) solid var(--bh-black);
  position: sticky;
  top: 0;
  z-index: 50;
}
.site-head__inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 12px var(--pad);
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}
.brand {
  text-decoration: none;
  color: var(--bh-black);
  display: flex;
  align-items: center;
  gap: 10px;
}
.brand:hover .brand__latin { background: var(--bh-yellow); }
.brand__mark { display: inline-flex; align-items: center; gap: 3px; margin-right: 4px; }
.brand__mark i { width: 11px; height: 11px; }
.brand__mark i:nth-child(1) { background: var(--bh-red); border-radius: var(--r-round); }
.brand__mark i:nth-child(2) { background: var(--bh-blue); border-radius: var(--r-square); }
.brand__mark i:nth-child(3) {
  background: transparent;
  width: 0;
  height: 0;
  border-left: 6px solid transparent;
  border-right: 6px solid transparent;
  border-bottom: 10px solid var(--bh-yellow);
}
.brand__latin {
  font-family: var(--display);
  font-size: 15px;
  font-weight: 900;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  padding: 2px 4px;
}
.brand__cn {
  font-size: 12.5px;
  color: var(--bh-black-55);
  letter-spacing: 0.06em;
  border-left: var(--bw-sm) solid var(--bh-black);
  padding-left: 10px;
}
.site-nav { margin-left: auto; display: flex; gap: 10px; flex-wrap: wrap; }
.site-nav a {
  font-family: var(--display);
  color: var(--bh-black);
  text-decoration: none;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  padding: 5px 12px;
  border: var(--bw-sm) solid transparent;
  border-radius: var(--r-square);
  transition: background 0.2s ease-out, border-color 0.2s ease-out,
    transform 0.2s ease-out;
}
.site-nav a:hover {
  background: var(--bh-yellow);
  border-color: var(--bh-black);
  transform: translateY(-1px);
}
.site-nav a[aria-current="page"] {
  background: var(--bh-black);
  color: var(--bh-white);
  border-color: var(--bh-black);
}

/* ------------------------------------------------------------------ 版心 */
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 var(--pad); }
.layout {
  display: grid;
  grid-template-columns: 232px minmax(0, 1fr);
  gap: 52px;
  align-items: start;
  padding: 34px 0 90px;
}
.layout--wide { grid-template-columns: minmax(0, 1fr); }

/* ------------------------------------------------------- 侧栏目录（书脊） */
.toc {
  position: sticky;
  top: 88px;
  max-height: calc(100vh - 110px);
  overflow: auto;
  font-size: 13.5px;
  line-height: 1.7;
  border-left: var(--bw) solid var(--bh-black);
  padding-left: 0;
}
.toc__title {
  font-family: var(--display);
  font-size: 11.5px;
  font-weight: 900;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--bh-white);
  background: var(--bh-black);
  margin: 0 0 10px;
  padding: 5px 10px;
  text-indent: 0;
}
.toc a {
  display: block;
  color: var(--bh-black-70);
  text-decoration: none;
  padding: 4px 10px 4px 12px;
  border-left: 6px solid transparent;
  margin-left: -4px;
  transition: background 0.2s ease-out, border-color 0.2s ease-out;
}
.toc a:hover { background: var(--bh-yellow-tint); border-left-color: var(--bh-black); }
.toc a.is-active {
  background: var(--bh-yellow);
  border-left-color: var(--bh-black);
  color: var(--bh-black);
  font-weight: 700;
}
.toc a.lv3 { padding-left: 24px; font-size: 12.5px; color: var(--bh-black-55); }
.toc__foot {
  margin-top: 18px;
  border-top: var(--bw-sm) solid var(--bh-black);
  padding-top: 10px;
}
.toc__foot a { font-size: 12.5px; color: var(--bh-black-55); }

/* ------------------------------------------------------------------ 文章 */
.article { max-width: var(--measure); }
.article--wide { max-width: none; }
.lead-col { max-width: 40em; }
.lead-col p { text-indent: 0; }

.ch-head {
  margin: 6px 0 40px;
  padding-bottom: 18px;
  border-bottom: var(--bw) solid var(--bh-black);
}
.ch-eyebrow {
  font-family: var(--display);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--bh-red);
  margin: 0 0 14px;
}
.ch-eyebrow::before {
  content: "";
  display: inline-block;
  width: 10px;
  height: 10px;
  background: var(--bh-red);
  margin-right: 9px;
}
h1 {
  font-family: var(--display);
  font-size: clamp(27px, 4.2vw, 40px);
  line-height: 1.25;
  margin: 0 0 18px;
  color: var(--bh-black);
  font-weight: 900;
  letter-spacing: 0.01em;
}
.ch-lede {
  font-size: 16.5px;
  color: var(--bh-black-70);
  border-left: 6px solid var(--bh-yellow);
  background: var(--bh-white);
  padding: 12px 18px;
  margin: 0;
  text-indent: 0;
}

h2 {
  font-family: var(--display);
  font-size: 22px;
  color: var(--bh-black);
  margin: 60px 0 20px;
  padding: 0 0 10px;
  border-bottom: var(--bw) solid var(--bh-black);
  font-weight: 900;
  line-height: 1.5;
  letter-spacing: 0.01em;
}
/* 每节标题前的几何标记，按顺序轮转形状与颜色（纯 CSS，不改 HTML） */
h2::before {
  content: "";
  display: inline-block;
  width: 14px;
  height: 14px;
  margin-right: 11px;
  vertical-align: -1px;
  background: var(--bh-red);
}
section:nth-of-type(3n + 2) h2::before {
  background: var(--bh-blue);
  border-radius: var(--r-round);
}
section:nth-of-type(3n + 3) h2::before {
  background: transparent;
  width: 0;
  height: 0;
  border-left: 8px solid transparent;
  border-right: 8px solid transparent;
  border-bottom: 14px solid var(--bh-yellow);
  vertical-align: -3px;
}

h3 {
  font-family: var(--display);
  font-size: 18px;
  color: var(--bh-black);
  margin: 36px 0 12px;
  font-weight: 700;
  letter-spacing: 0.01em;
  padding-left: 12px;
  border-left: 6px solid var(--bh-blue);
}
h4 {
  font-family: var(--display);
  font-size: 16px;
  color: var(--bh-black);
  margin: 24px 0 10px;
  font-weight: 700;
}
h2 + h3 { margin-top: 24px; }

p { margin: 0 0 1.05em; text-indent: 2em; }
.article p a,
.article li a {
  color: var(--bh-blue);
  text-decoration: none;
  border-bottom: var(--bw-sm) solid var(--bh-blue);
  font-weight: 700;
}
.article p a:hover,
.article li a:hover { background: var(--bh-yellow); color: var(--bh-black); }
strong, b { font-weight: 700; color: var(--bh-black); }
em { font-style: normal; background: var(--bh-yellow-tint); padding: 0 3px; }

ul, ol { padding-left: 1.6em; margin: 0 0 1.15em; }
li { margin: 0.4em 0; }
li > ul, li > ol { margin: 0.35em 0 0.5em; }
ul { list-style: none; padding-left: 1.2em; }
ul > li::before {
  content: "";
  display: inline-block;
  width: 7px;
  height: 7px;
  background: var(--bh-red);
  margin-right: 10px;
  margin-left: -1.2em;
  vertical-align: 2px;
}
ol { list-style: decimal; }
ol > li::marker { color: var(--bh-blue); font-weight: 700; }

hr { border: 0; border-top: var(--bw) solid var(--bh-black); margin: 48px 0; }

blockquote {
  margin: 1.5em 0;
  padding: 16px 22px;
  border: var(--bw-sm) solid var(--bh-black);
  border-left: var(--bw) solid var(--bh-black);
  background: var(--bh-yellow-tint);
  color: var(--bh-black);
  box-shadow: var(--shadow-md);
}
blockquote p { text-indent: 0; margin: 0.5em 0; }
blockquote p:last-child { margin-bottom: 0; }

/* ------------------------------------------------------------------ 代码 */
code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--bh-white);
  border: 1px solid var(--bh-black);
  padding: 0.1em 0.34em;
  border-radius: var(--r-square);
  color: var(--bh-black);
  word-break: break-word;
}
pre {
  font-family: var(--mono);
  font-size: 13.5px;
  line-height: 1.75;
  background: var(--bh-white);
  border: var(--bw-sm) solid var(--bh-black);
  border-left: var(--bw) solid var(--bh-black);
  border-radius: var(--r-square);
  padding: 16px 18px;
  overflow-x: auto;
  margin: 1.5em 0;
  text-indent: 0;
  box-shadow: var(--shadow-md);
}
pre code {
  background: none;
  border: 0;
  padding: 0;
  color: var(--bh-black);
  font-size: inherit;
}
.code-cap {
  font-family: var(--display);
  font-size: 12.5px;
  font-weight: 700;
  color: var(--bh-black-70);
  margin: -1.1em 0 1.8em;
  padding-left: 10px;
  border-left: 6px solid var(--bh-yellow);
  text-indent: 0;
}

/* ------------------------------------------------------------------ 表格 */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.6em 0;
  font-size: 15.5px;
  line-height: 1.7;
  background: var(--bh-white);
  border: var(--bw-sm) solid var(--bh-black);
  box-shadow: var(--shadow-sm);
}
th, td {
  border: var(--bw-sm) solid var(--bh-black);
  padding: 8px 11px;
  text-align: left;
  vertical-align: top;
}
th {
  background: var(--bh-black);
  color: var(--bh-white);
  font-family: var(--display);
  font-weight: 700;
  letter-spacing: 0.02em;
  text-indent: 0;
}
td { text-indent: 0; background: var(--bh-white); }
tbody tr:nth-child(even) td { background: var(--bh-canvas); }

/* ------------------------------------------------ 组件：目标卡 / 提示块 */
.goal-box, .link-box, .note, .warn, .tip, .idea, .ledger {
  margin: 1.6em 0;
  padding: 18px 22px;
  border: var(--bw-sm) solid var(--bh-black);
  border-radius: var(--r-square);
  background: var(--bh-white);
  box-shadow: var(--shadow-md);
  text-indent: 0;
}
/* 每类提示块用一条粗色条声明语义，颜色不混用 */
.goal-box { border-left: 10px solid var(--bh-blue); }
.link-box { border-left: 10px solid var(--bh-red); }
.note { border-left: 10px solid var(--bh-blue); }
.tip { border-left: 10px solid var(--bh-yellow); }
.warn { border-left: 10px solid var(--bh-red); background: var(--bh-yellow-tint); }
.ledger { border-left: 10px solid var(--bh-black); }
.idea {
  border-left: 10px solid var(--bh-blue);
  background-image: radial-gradient(var(--bh-black-16) 1.5px, transparent 1.5px);
  background-size: 14px 14px;
}
.goal-box h3, .goal-box h4 { margin-top: 0; }
.goal-box ul > li::before { background: var(--bh-blue); }
.goal-box > :last-child,
.link-box > :last-child,
.note > :last-child,
.tip > :last-child,
.warn > :last-child,
.idea > :last-child,
.ledger > :last-child { margin-bottom: 0; }
.note > :first-child,
.tip > :first-child,
.warn > :first-child,
.idea > :first-child,
.ledger > :first-child,
.link-box > :first-child { margin-top: 0; }
.note p, .tip p, .warn p, .idea p, .ledger p, .link-box p { text-indent: 0; }
.link-box p { margin: 0.35em 0; }

.tag-label {
  display: inline-block;
  font-family: var(--display);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  background: var(--bh-black);
  color: var(--bh-white);
  padding: 2px 9px;
  margin-right: 10px;
  vertical-align: 1px;
}

/* ------------------------------------------- 术语：正文里可点击的词 */
.term {
  color: var(--bh-blue);
  border-bottom: 2px dotted var(--bh-blue);
  cursor: help;
  text-decoration: none;
  transition: background 0.15s ease-out;
}
.term:hover { background: var(--bh-yellow); border-bottom-style: solid; }
.term:focus-visible { outline: 3px solid var(--bh-blue); outline-offset: 2px; }

/* ----------------------------------------------- 折叠答案（自查题） */
details {
  margin: 0.8em 0 1.2em;
  border: var(--bw-sm) solid var(--bh-black);
  background: var(--bh-white);
  border-radius: var(--r-square);
  padding: 0;
}
summary {
  cursor: pointer;
  font-family: var(--display);
  font-size: 13.5px;
  font-weight: 700;
  color: var(--bh-white);
  background: var(--bh-black);
  padding: 7px 14px;
  list-style: none;
  user-select: none;
}
summary::-webkit-details-marker { display: none; }
summary::before { content: "▸ "; }
details[open] > summary { background: var(--bh-red); }
details[open] > summary::before { content: "▾ "; }
details > *:not(summary) { padding: 4px 16px; }
details p { text-indent: 0; }
details[open] > *:not(summary) { background: var(--bh-yellow-tint); }
details > *:last-child { padding-bottom: 12px; }

/* ---------------------------------------------------- 自查题 / 自问自答 */
.quiz { counter-reset: q; padding-left: 0; list-style: none; }
.quiz > li {
  counter-increment: q;
  padding-left: 3.2em;
  position: relative;
  margin: 1.6em 0;
}
.quiz > li::before {
  content: "Q" counter(q);
  position: absolute;
  left: 0;
  top: 0.15em;
  width: 2.2em;
  height: 2.2em;
  line-height: 2.2em;
  text-align: center;
  background: var(--bh-red);
  color: var(--bh-white);
  font-family: var(--display);
  font-size: 12px;
  font-weight: 900;
  border: var(--bw-sm) solid var(--bh-black);
}
.reflect { list-style: none; padding-left: 0; }
.reflect > li {
  padding-left: 3.1em;
  position: relative;
  margin: 1.1em 0;
  color: var(--bh-black-70);
}
.reflect > li::before {
  content: "？";
  position: absolute;
  left: 0;
  top: 0.1em;
  width: 2.1em;
  height: 2.1em;
  line-height: 2.1em;
  text-align: center;
  background: var(--bh-blue);
  color: var(--bh-white);
  font-family: var(--display);
  font-weight: 900;
  border: var(--bw-sm) solid var(--bh-black);
  border-radius: var(--r-round);
}

/* ---------------------------------------------------- 术语速览 chips */
.term-chips { display: flex; flex-wrap: wrap; gap: 9px; padding: 0; list-style: none; }
.term-chips > li { margin: 0; }
.term-chips > li::before { content: none; }
.term-chips .term {
  border: var(--bw-sm) solid var(--bh-black);
  border-radius: var(--r-square);
  padding: 3px 12px;
  font-size: 14px;
  background: var(--bh-white);
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease-out, background 0.2s ease-out;
}
.term-chips .term:hover { transform: translateY(-2px); background: var(--bh-yellow); }

/* ------------------------------------------------ 章节页脚：上下章导航 */
.ch-nav {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  margin-top: 64px;
  padding-top: 24px;
  border-top: var(--bw) solid var(--bh-black);
  font-size: 14.5px;
}
.ch-nav a {
  display: block;
  flex: 1 1 0;
  max-width: 48%;
  color: var(--bh-black);
  text-decoration: none;
  background: var(--bh-white);
  border: var(--bw-sm) solid var(--bh-black);
  box-shadow: var(--shadow-sm);
  padding: 12px 16px;
  font-family: var(--display);
  font-weight: 700;
  transition: transform 0.2s ease-out, background 0.2s ease-out;
}
.ch-nav a:hover { background: var(--bh-yellow); transform: translateY(-2px); }
.ch-nav a:active { transform: translate(2px, 2px); box-shadow: none; }
.ch-nav span {
  display: block;
  font-family: var(--display);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bh-red);
  margin-bottom: 4px;
}

/* ------------------------------------------------------------- 读完按钮 */
.readbtn {
  margin: 28px 0 0;
  font-family: var(--display);
  font-size: 14.5px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--bh-white);
  background: var(--bh-red);
  border: var(--bw-sm) solid var(--bh-black);
  border-radius: var(--r-square);
  box-shadow: var(--shadow-md);
  padding: 9px 22px;
  cursor: pointer;
  transition: transform 0.2s ease-out, box-shadow 0.2s ease-out;
}
.readbtn:hover { transform: translateY(-2px); box-shadow: 6px 6px 0 0 var(--bh-black); }
.readbtn:active { transform: translate(2px, 2px); box-shadow: none; }
.readbtn.is-done { background: var(--bh-yellow); color: var(--bh-black); }

/* ------------------------------------------------------------------ 首页 */
.hero {
  padding: 64px 0 52px;
  border-bottom: var(--bw) solid var(--bh-black);
  background-color: var(--bh-canvas);
  background-image: radial-gradient(var(--bh-black-16) 1.5px, transparent 1.5px);
  background-size: 18px 18px;
  position: relative;
  overflow: hidden;
}
.hero > .wrap {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  gap: 48px;
  align-items: center;
}
.hero__text { min-width: 0; }
.hero__title {
  font-family: var(--display);
  font-size: clamp(38px, 7vw, 84px);
  letter-spacing: 0.01em;
  color: var(--bh-black);
  margin: 0 0 10px;
  font-weight: 900;
  line-height: 0.98;
  text-transform: uppercase;
}
.hero__cn {
  display: inline-block;
  font-family: var(--display);
  font-size: clamp(14px, 1.6vw, 17px);
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--bh-black);
  background: var(--bh-yellow);
  border: var(--bw-sm) solid var(--bh-black);
  box-shadow: var(--shadow-sm);
  padding: 5px 14px;
  margin: 0 0 30px;
  text-indent: 0;
}
.hero__lede { max-width: 34em; font-size: 17.5px; color: var(--bh-black-70); text-indent: 0; }
.hero__meta {
  font-family: var(--display);
  font-size: 13px;
  color: var(--bh-black-70);
  margin-top: 30px;
  text-indent: 0;
  border-top: var(--bw-sm) solid var(--bh-black);
  padding-top: 12px;
}
.hero__meta b { font-weight: 900; color: var(--bh-black); }

/* 首页右侧的几何构图：圆、方、三角与空心方叠压 */
.hero__art {
  position: relative;
  height: 320px;
  border: var(--bw) solid var(--bh-black);
  background: var(--bh-white);
  box-shadow: var(--shadow-lg);
}
.hero__art .shape { position: absolute; }
.hero__art .shape--circle {
  width: 132px;
  height: 132px;
  background: var(--bh-blue);
  top: 26px;
  left: 28px;
}
.hero__art .shape--square {
  width: 108px;
  height: 108px;
  background: var(--bh-red);
  top: 104px;
  left: 118px;
}
.hero__art .shape--triangle {
  border-left-width: 44px;
  border-right-width: 44px;
  border-bottom-width: 76px;
  border-bottom-color: var(--bh-yellow);
  bottom: 26px;
  left: 34px;
}
.hero__art .shape--outline {
  width: 128px;
  height: 128px;
  border-width: var(--bw);
  bottom: 30px;
  right: 26px;
}

.section-title {
  font-family: var(--display);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--bh-white);
  background: var(--bh-black);
  display: inline-block;
  padding: 5px 14px;
  margin: 64px 0 22px;
  text-indent: 0;
}

/* 学习地图 */
.road { list-style: none; padding: 0; margin: 0; }
.road > li { margin: 0; }
.road > li::before { content: none; }
.road a.card {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr) auto;
  gap: 18px;
  align-items: baseline;
  padding: 18px;
  border: var(--bw-sm) solid var(--bh-black);
  border-bottom: 0;
  background: var(--bh-white);
  text-decoration: none;
  color: inherit;
  position: relative;
  transition: transform 0.2s ease-out, background 0.2s ease-out;
}
.road li:last-child a.card { border-bottom: var(--bw-sm) solid var(--bh-black); }
.road a.card:hover { background: var(--bh-yellow-tint); transform: translateX(4px); }
/* 卡片右上角的几何角标：三形状 + 三原色按序轮转 */
.road a.card::after {
  content: "";
  position: absolute;
  top: 12px;
  right: 12px;
  width: 12px;
  height: 12px;
  background: var(--bh-red);
}
.road li:nth-child(3n + 2) a.card::after {
  background: var(--bh-blue);
  border-radius: var(--r-round);
}
.road li:nth-child(3n + 3) a.card::after {
  background: transparent;
  width: 0;
  height: 0;
  border-left: 7px solid transparent;
  border-right: 7px solid transparent;
  border-bottom: 12px solid var(--bh-yellow);
}
.card__num {
  font-family: var(--display);
  font-size: 30px;
  font-weight: 900;
  color: var(--bh-white);
  background: var(--bh-black);
  text-align: center;
  line-height: 1.2;
  padding: 4px 0;
}
.card__title {
  font-family: var(--display);
  font-size: 17.5px;
  color: var(--bh-black);
  font-weight: 900;
  margin: 0 0 5px;
  display: block;
  letter-spacing: 0.01em;
}
.card__desc {
  font-size: 14.5px;
  color: var(--bh-black-70);
  margin: 0;
  text-indent: 0;
  line-height: 1.75;
  display: block;
}
.card__tags {
  font-family: var(--display);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--bh-black-55);
  margin: 8px 0 0;
  text-indent: 0;
  display: block;
}
.card__state {
  font-family: var(--display);
  font-size: 11.5px;
  color: var(--bh-black-38);
  white-space: nowrap;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding-right: 20px;
}
.card__state.is-done { color: var(--bh-red); font-weight: 900; }

.progress-line {
  display: flex;
  align-items: center;
  gap: 14px;
  font-family: var(--display);
  font-size: 13px;
  color: var(--bh-black-70);
  text-indent: 0;
  margin-bottom: 14px;
}
.progress-track {
  flex: 1;
  height: 14px;
  background: var(--bh-white);
  border: var(--bw-sm) solid var(--bh-black);
  position: relative;
}
.progress-track i {
  position: absolute;
  inset: 0 auto 0 0;
  background: var(--bh-red);
  width: 0;
}

/* 两栏小卡片 */
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 24px; }
.panel {
  border: var(--bw-sm) solid var(--bh-black);
  border-radius: var(--r-square);
  padding: 22px;
  background: var(--bh-white);
  box-shadow: var(--shadow-md);
  position: relative;
  transition: transform 0.2s ease-out;
}
.panel:hover { transform: translateY(-3px); }
.panel h3 { margin-top: 0; border-left-color: var(--bh-red); }
.panel p { text-indent: 0; font-size: 15.5px; }
.panel::after {
  content: "";
  position: absolute;
  top: 10px;
  right: 10px;
  width: 11px;
  height: 11px;
  background: var(--bh-yellow);
}
.grid2 .panel:nth-child(2n)::after { background: var(--bh-red); border-radius: var(--r-round); }
.grid2 .panel:nth-child(3n)::after {
  background: transparent;
  width: 0;
  height: 0;
  border-left: 6px solid transparent;
  border-right: 6px solid transparent;
  border-bottom: 11px solid var(--bh-blue);
}

/* OWL 卡片 */
.owl-card {
  border: var(--bw) solid var(--bh-black);
  border-left: 12px solid var(--bh-red);
  padding: 26px 28px;
  background: var(--bh-white);
  box-shadow: var(--shadow-lg);
}
.owl-card h3 { margin-top: 0; border-left: 0; padding-left: 0; font-size: 20px; }
.owl-card p { text-indent: 0; }
.kv {
  font-family: var(--display);
  font-size: 13.5px;
  color: var(--bh-black-70);
  line-height: 1.8;
}
.kv b { color: var(--bh-black); font-weight: 900; }

/* ----------------------------------------------------------- 术语总表 */
.glossary-tools { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; margin: 28px 0 12px; }
.glossary-tools input {
  flex: 1 1 260px;
  font-family: var(--display);
  font-size: 15px;
  font-weight: 500;
  padding: 11px 15px;
  border: var(--bw-sm) solid var(--bh-black);
  border-radius: var(--r-square);
  background: var(--bh-white);
  color: var(--bh-black);
  box-shadow: var(--shadow-sm);
}
.glossary-tools input:focus { outline: 3px solid var(--bh-blue); outline-offset: 2px; }
.chiprow { display: flex; gap: 9px; flex-wrap: wrap; }
.chipbtn {
  font-family: var(--display);
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 5px 14px;
  border: var(--bw-sm) solid var(--bh-black);
  border-radius: var(--r-square);
  background: var(--bh-white);
  color: var(--bh-black);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease-out, background 0.2s ease-out;
}
.chipbtn:hover { background: var(--bh-yellow); transform: translateY(-2px); }
.chipbtn:active { transform: translate(2px, 2px); box-shadow: none; }
.chipbtn.is-on { background: var(--bh-black); color: var(--bh-white); }

.gloss-group { margin: 44px 0 0; }
.gloss-group > h2 {
  font-size: 17px;
  letter-spacing: 0.08em;
  border-bottom: 0;
  border-left: 10px solid var(--bh-blue);
  background: var(--bh-black);
  color: var(--bh-white);
  padding: 7px 14px;
  margin-bottom: 0;
}
.gloss-group > h2::before { content: none; }
.gloss-item {
  padding: 16px 18px;
  border: var(--bw-sm) solid var(--bh-black);
  border-top: 0;
  background: var(--bh-white);
  scroll-margin-top: 100px;
}
.gloss-item:last-child { box-shadow: var(--shadow-sm); }
.gloss-item:target,
.gloss-item.is-hit { background: var(--bh-yellow); }
.gloss-item__term {
  font-family: var(--display);
  font-size: 18px;
  color: var(--bh-black);
  font-weight: 900;
  margin: 0;
  text-indent: 0;
}
.gloss-item__full {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--bh-blue);
  margin: 3px 0 0;
  text-indent: 0;
  word-break: break-word;
}
.gloss-item__zh {
  font-size: 14.5px;
  color: var(--bh-black-55);
  margin: 2px 0 8px;
  text-indent: 0;
}
.gloss-item__desc { font-size: 15.5px; margin: 0; text-indent: 0; }
.gloss-item__desc p { text-indent: 0; }
.gloss-item__cat {
  font-family: var(--display);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--bh-black-38);
}
.gloss-empty { color: var(--bh-black-38); padding: 30px 0; }

/* ----------------------------------------------------------- 术语弹窗 */
#term-modal {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background: rgba(18, 18, 18, 0.72);
}
#term-modal.is-open { display: flex; }
.term-card {
  position: relative;
  background: var(--bh-white);
  border: var(--bw) solid var(--bh-black);
  border-top: 14px solid var(--bh-red);
  max-width: 580px;
  width: 100%;
  max-height: 84vh;
  overflow: auto;
  padding: 26px 28px 22px;
  border-radius: var(--r-square);
  box-shadow: var(--shadow-lg);
}
.term-card__cat {
  font-family: var(--display);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--bh-white);
  background: var(--bh-black);
  display: inline-block;
  padding: 2px 10px;
  margin: 0 0 10px;
  text-indent: 0;
}
.term-card__term {
  font-family: var(--display);
  font-size: 26px;
  color: var(--bh-black);
  margin: 0;
  text-indent: 0;
  line-height: 1.3;
  font-weight: 900;
}
.term-card__full {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--bh-blue);
  margin: 8px 0 0;
  text-indent: 0;
  word-break: break-word;
}
.term-card__zh {
  font-size: 15px;
  color: var(--bh-black-55);
  margin: 4px 0 16px;
  text-indent: 0;
}
.term-card__desc { text-indent: 0; font-size: 16px; }
.term-card__desc p { text-indent: 0; }
.term-card__desc ul { font-size: 15.5px; }
.term-card__foot {
  margin-top: 20px;
  padding-top: 14px;
  border-top: var(--bw-sm) solid var(--bh-black);
  font-size: 13.5px;
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.term-card__foot a {
  color: var(--bh-black);
  text-decoration: none;
  font-family: var(--display);
  font-weight: 700;
  border-bottom: var(--bw-sm) solid var(--bh-red);
}
.term-card__foot a:hover { background: var(--bh-yellow); }
.term-card__x {
  position: absolute;
  top: 12px;
  right: 14px;
  width: 34px;
  height: 34px;
  border: var(--bw-sm) solid var(--bh-black);
  background: var(--bh-white);
  color: var(--bh-black);
  font-size: 20px;
  line-height: 1;
  cursor: pointer;
  font-family: var(--display);
  font-weight: 900;
  transition: transform 0.2s ease-out, background 0.2s ease-out;
}
.term-card__x:hover { background: var(--bh-yellow); transform: rotate(90deg); }
.term-rel { font-size: 13.5px; color: var(--bh-black-55); margin-top: 14px; text-indent: 0; }
.term-rel .term { margin-right: 8px; }
.term-close { display: none; }

/* ------------------------------------------------------------------ 页脚 */
.site-foot {
  background: var(--bh-black);
  border-top: var(--bw) solid var(--bh-black);
  margin-top: 48px;
  padding: 34px 0 60px;
  font-size: 13.5px;
  color: rgba(255, 255, 255, 0.72);
}
.site-foot p { text-indent: 0; margin: 0.35em 0; }
.site-foot b {
  font-family: var(--display);
  color: var(--bh-white);
  letter-spacing: 0.04em;
}
.site-foot a {
  color: var(--bh-yellow);
  border-bottom: 1px solid currentColor;
  text-decoration: none;
}
.site-foot__ver {
  font-family: var(--display);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.45) !important;
  margin-top: 14px !important;
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: 12px;
}

/* ------------------------------------------------------------------ 响应式 */
.toc-toggle { display: none; }
@media (max-width: 900px) {
  body { font-size: 17px; }
  :root { --bw: 3px; --shadow-lg: 6px 6px 0 0 var(--bh-black); }
  .layout { grid-template-columns: minmax(0, 1fr); gap: 0; padding-top: 20px; }
  .toc {
    position: static;
    max-height: none;
    border: var(--bw-sm) solid var(--bh-black);
    border-left: var(--bw) solid var(--bh-black);
    background: var(--bh-white);
    padding: 12px 14px 14px;
    margin-bottom: 26px;
    display: none;
    box-shadow: var(--shadow-sm);
  }
  .toc.is-open { display: block; }
  .toc__title { margin: -12px -14px 10px; }
  .toc-toggle {
    display: inline-block;
    margin: 0 0 16px;
    font-family: var(--display);
    font-size: 13.5px;
    font-weight: 700;
    color: var(--bh-white);
    background: var(--bh-blue);
    border: var(--bw-sm) solid var(--bh-black);
    border-radius: var(--r-square);
    box-shadow: var(--shadow-sm);
    padding: 7px 20px;
    cursor: pointer;
  }
  .toc-toggle:active { transform: translate(2px, 2px); box-shadow: none; }
  h1 { font-size: 25px; }
  h2 { font-size: 20px; margin-top: 46px; }
  p { text-indent: 1.6em; }
  .hero { padding: 40px 0 36px; }
  .hero > .wrap { grid-template-columns: minmax(0, 1fr); gap: 28px; }
  .hero__art { height: 220px; order: -1; }
  .hero__art .shape--circle { width: 92px; height: 92px; top: 18px; left: 18px; }
  .hero__art .shape--square { width: 76px; height: 76px; top: 74px; left: 84px; }
  .hero__art .shape--outline { width: 92px; height: 92px; bottom: 20px; right: 18px; }
  .road a.card { grid-template-columns: 52px minmax(0, 1fr); padding: 14px; }
  .road a.card:hover { transform: none; }
  .card__state { grid-column: 2; padding-right: 0; }
  .road a.card::after { top: 8px; right: 8px; width: 9px; height: 9px; }
  .ch-nav { flex-direction: column; }
  .ch-nav a { max-width: 100%; }
  .gloss-group > h2 { font-size: 15px; }
  .term-card { border-top-width: 10px; padding: 22px 18px 18px; }
}

@media print {
  .site-head, .toc, .toc-toggle, .ch-nav, .readbtn, #readbar, #term-modal,
  .hero__art { display: none !important; }
  .layout { display: block; padding: 0; }
  body { font-size: 12pt; background: #fff; color: #000; }
  .article a { color: #000; border-bottom: 0; }
  h2 { page-break-after: avoid; }
  pre, table, .goal-box, .note, .tip, .warn, .idea, .ledger, blockquote {
    box-shadow: none !important;
  }
}

/* 尊重「减少动态效果」的系统偏好（可达性） */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
  .road a.card:hover,
  .panel:hover,
  .chipbtn:hover,
  .term-chips .term:hover,
  .readbtn:hover,
  .ch-nav a:hover { transform: none !important; }
  .term-card__x:hover { transform: none !important; }
}