/* ============================================================
   德赢中心 / assets/site.css
   共享层：reset、变量、中文排版、头部命令栏、页脚、通用组件
   ============================================================ */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scrollbar-color: #9AA7B4 #0B1A2B;
}

body,
h1, h2, h3, h4, h5, p,
ul, ol, figure, blockquote { margin: 0; }

ul, ol { padding: 0; list-style: none; }

img, svg { display: block; max-width: 100%; }

button, input { font: inherit; color: inherit; }

button { background: none; border: 0; cursor: pointer; }

a { color: inherit; }

hr { border: 0; }

[hidden] { display: none !important; }

/* ---------- 2. Tokens ---------- */
:root {
  /* 自然矿物色系 */
  --ink: #0B1A2B;
  --ink-2: #12293F;
  --signal: #FF6A2B;
  --signal-soft: #FFB37A;
  --sage: #6F8A7B;
  --moss: #2F6B58;
  --clay: #C8927A;
  --rock: #9AA7B4;
  --paper: #F4F1E8;
  --sheet: #E8E4D8;

  --line: rgba(154, 167, 180, 0.26);
  --line-strong: rgba(154, 167, 180, 0.48);
  --ink-line: rgba(11, 26, 43, 0.16);

  /* 结构 */
  --wrap: 1240px;
  --gutter: clamp(16px, 3vw, 40px);
  --row: clamp(16px, 2.2vw, 28px);
  --head-h: 48px;
  --rail-h: 40px;

  /* 字体 */
  --font-head: "HarmonyOS Sans SC Condensed", "Source Han Sans Condensed",
    "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", "Noto Sans SC",
    system-ui, sans-serif;
  --font-body: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "SimSun",
    "PingFang SC", Georgia, serif;
  --font-ui: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei",
    system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", "Cascadia Mono", "Consolas",
    "Menlo", monospace;

  /* 动效 */
  --step: 180ms cubic-bezier(0.2, 0.7, 0.3, 1);
  --paper-shadow: 0 1px 0 rgba(232, 228, 216, 0.14),
    0 16px 30px -22px rgba(0, 0, 0, 0.7);
}

/* ---------- 3. 基础排版 ---------- */
body {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: 0.005em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: var(--font-head);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.02em;
  color: var(--paper);
}

h1 { font-size: clamp(30px, 4.4vw, 48px); }
h2 { font-size: clamp(22px, 2.4vw, 30px); }
h3 { font-size: 20px; }
h4 { font-size: 17px; }

p { font-size: 17px; }

strong { font-weight: 700; color: var(--paper); }

::selection { background: var(--signal); color: var(--ink); }

:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ---------- 4. 容器与网格 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.grid { display: grid; gap: var(--row); }
.grid--2 { display: grid; gap: var(--row); grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { display: grid; gap: var(--row); grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { display: grid; gap: var(--row); grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid--split {
  display: grid;
  gap: var(--row);
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  align-items: start;
}

.stack { display: grid; gap: var(--row); }

/* ---------- 5. 材质层：叠层 / 印刷边框 / 网格纹理 ---------- */
.sheet {
  position: relative;
  isolation: isolate;
  background: var(--ink-2);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  padding: clamp(18px, 2.4vw, 28px);
  box-shadow: var(--paper-shadow);
  transition: transform var(--step), box-shadow var(--step),
    border-color var(--step);
}

.sheet:hover {
  transform: translateY(-2px);
  border-color: rgba(255, 179, 122, 0.5);
  box-shadow: 0 2px 0 rgba(232, 228, 216, 0.16),
    0 24px 36px -22px rgba(0, 0, 0, 0.85);
}

.sheet--stack::after {
  content: "";
  position: absolute;
  inset: 8px -8px -8px 8px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: rgba(232, 228, 216, 0.04);
  z-index: -1;
  pointer-events: none;
}

.plate {
  position: relative;
  border: 1px solid var(--line-strong);
  background: rgba(232, 228, 216, 0.03);
  padding: clamp(18px, 2.6vw, 34px);
}

.plate::before {
  content: "";
  position: absolute;
  inset: 5px;
  border: 1px solid var(--line);
  pointer-events: none;
}

.grid-tex {
  background-image:
    linear-gradient(to right, var(--line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line) 1px, transparent 1px);
  background-size: 64px 64px;
  background-position: -1px -1px;
}

/* ---------- 6. 文字件 ---------- */
.mono {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: 0.04em;
  line-height: 1.6;
  padding: 2px 6px;
  background: rgba(11, 26, 43, 0.55);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  color: var(--signal-soft);
}

.prose {
  max-width: 68ch;
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  color: rgba(244, 241, 232, 0.9);
}

.prose > * + * { margin-top: 1em; }
.prose a {
  color: var(--signal-soft);
  text-underline-offset: 3px;
}
.prose a:hover { color: var(--signal); }

.rule {
  height: 1px;
  background: var(--line);
  margin: 0;
  border: 0;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-strong);
  margin-bottom: clamp(18px, 2.4vw, 28px);
}

.section-head__no {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--signal);
}

.section-head__title {
  margin: 0;
  font-size: clamp(20px, 2.2vw, 26px);
}

/* ---------- 7. 状态标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  line-height: 1.6;
  padding: 2px 7px;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  color: var(--rock);
  white-space: nowrap;
}

.tag--signal {
  background: var(--signal);
  border-color: var(--signal);
  color: var(--ink);
  font-weight: 700;
}

.tag--sage {
  background: rgba(111, 138, 123, 0.14);
  border-color: rgba(111, 138, 123, 0.6);
  color: #A7C0AF;
}

.tag--clay {
  background: rgba(200, 146, 122, 0.12);
  border-color: rgba(200, 146, 122, 0.6);
  color: var(--clay);
}

/* ---------- 8. 按钮 / 复制件 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-family: var(--font-ui);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: 0.01em;
  padding: 9px 16px;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  text-decoration: none;
  white-space: nowrap;
  transition: background var(--step), color var(--step),
    border-color var(--step), transform var(--step);
}

.btn--xs {
  font-size: 12.5px;
  padding: 5px 10px;
  letter-spacing: 0.02em;
}

.btn--signal {
  background: var(--signal);
  border-color: var(--signal);
  color: var(--ink);
}

.btn--signal:hover {
  background: var(--signal-soft);
  border-color: var(--signal-soft);
}

.btn--ghost {
  background: transparent;
  border-color: var(--line-strong);
  color: var(--paper);
}

.btn--ghost:hover {
  border-color: var(--signal);
  color: var(--signal);
  background: rgba(255, 106, 43, 0.1);
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  padding: 4px 9px;
  background: var(--ink-2);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  color: var(--signal-soft);
  transition: background var(--step), color var(--step),
    border-color var(--step);
}

.copy-btn:hover {
  background: rgba(255, 106, 43, 0.12);
  border-color: var(--signal);
  color: var(--signal);
}

.copy-btn[data-copied] {
  background: var(--signal);
  border-color: var(--signal);
  color: var(--ink);
}

/* ---------- 9. 面包屑 ---------- */
.crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--rock);
}

.crumb a {
  color: var(--rock);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--step), border-color var(--step);
}

.crumb a:hover {
  color: var(--signal);
  border-bottom-color: var(--signal);
}

.crumb__sep { color: rgba(154, 167, 180, 0.55); }

.crumb [aria-current="page"] { color: var(--paper); }

.crumb--paper { color: #5A6672; }
.crumb--paper a { color: #5A6672; }
.crumb--paper a:hover { color: #C1500F; border-bottom-color: #C1500F; }
.crumb--paper .crumb__sep { color: rgba(11, 26, 43, 0.35); }
.crumb--paper [aria-current="page"] { color: var(--ink); }

/* ---------- 10. 米白阅读区 ---------- */
.on-paper {
  background: var(--paper);
  color: var(--ink);
}

.on-paper h1,
.on-paper h2,
.on-paper h3,
.on-paper h4 { color: var(--ink); }

.on-paper p { color: #1E2C3A; }

.on-paper .prose { color: #1E2C3A; }
.on-paper .prose a { color: #B4470F; }
.on-paper .prose strong { color: var(--ink); }

.on-paper .section-head { border-bottom-color: var(--ink-line); }
.on-paper .rule { background: var(--ink-line); }
.on-paper .sheet {
  background: var(--sheet);
  border-color: rgba(11, 26, 43, 0.2);
  box-shadow: 0 1px 0 rgba(11, 26, 43, 0.08),
    0 16px 26px -22px rgba(11, 26, 43, 0.5);
}
.on-paper .sheet:hover { border-color: rgba(255, 106, 43, 0.6); }
.on-paper .tag { color: #4C5A67; border-color: rgba(11, 26, 43, 0.28); }
.on-paper .mono {
  background: var(--ink);
  color: var(--signal-soft);
  border-color: var(--ink);
}
.on-paper .plate {
  border-color: rgba(11, 26, 43, 0.28);
  background: rgba(11, 26, 43, 0.03);
}
.on-paper .plate::before { border-color: rgba(11, 26, 43, 0.14); }
.on-paper .grid-tex {
  background-image:
    linear-gradient(to right, rgba(11, 26, 43, 0.09) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(11, 26, 43, 0.09) 1px, transparent 1px);
}

/* ---------- 11. 图片容器 ---------- */
.figure { display: grid; gap: 10px; margin: 0; }

.figure__media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  background: var(--ink-2);
}

.figure__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(154, 167, 180, 0.18) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(154, 167, 180, 0.18) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
}

.figure__media[data-ratio="wide"] { aspect-ratio: 21 / 9; }
.figure__media[data-ratio="square"] { aspect-ratio: 1 / 1; }
.figure__media[data-ratio="tall"] { aspect-ratio: 3 / 4; }

.figure__img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure__caption {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--rock);
}

.on-paper .figure__caption { color: #5A6672; }

/* ============================================================
   12. 头部：命令栏 + 索引条
   ============================================================ */
.skip-link {
  position: absolute;
  left: 12px;
  top: 0;
  z-index: 200;
  transform: translateY(-140%);
  background: var(--signal);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 700;
  padding: 10px 16px;
  border-radius: 0 0 2px 2px;
  text-decoration: none;
  transition: transform var(--step);
}

.skip-link:focus,
.skip-link:focus-visible { transform: translateY(0); }

.site-head {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--ink);
  border-bottom: 1px solid var(--line-strong);
}

.cmd {
  position: relative;
  background: var(--ink);
}

.cmd__inner {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.4vw, 22px);
  min-height: var(--head-h);
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  flex: 0 0 auto;
  text-decoration: none;
  color: var(--paper);
}

.brand__mark {
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  background: var(--signal);
  color: var(--ink);
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 15px;
  line-height: 1;
  border-radius: 2px;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand__name {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 16px;
  letter-spacing: 0.04em;
}

.brand__tagline {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  color: var(--rock);
  margin-top: 2px;
}

.brand:hover .brand__tagline { color: var(--signal-soft); }

/* 主导航 */
.nav {
  flex: 1 1 auto;
  min-width: 0;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav__item { flex: 0 0 auto; }

.nav__link {
  display: block;
  padding: 6px 9px;
  font-family: var(--font-ui);
  font-size: 13.5px;
  line-height: 1.5;
  color: rgba(244, 241, 232, 0.78);
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 2px;
  white-space: nowrap;
  transition: background var(--step), color var(--step),
    border-color var(--step);
}

.nav__link:hover {
  color: var(--paper);
  background: var(--ink-2);
  border-color: var(--line);
}

.nav__link[aria-current="page"] {
  color: var(--ink);
  background: var(--paper);
  border-color: var(--paper);
  box-shadow: inset 0 -2px 0 var(--signal);
  font-weight: 600;
}

/* 命令栏工具区 */
.cmd__tools {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  flex: 0 0 auto;
}

.idx-filter {
  position: relative;
  display: flex;
  align-items: center;
  gap: 6px;
  height: 28px;
  padding: 0 8px;
  background: var(--ink-2);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  transition: border-color var(--step), box-shadow var(--step);
}

.idx-filter:focus-within {
  border-color: var(--signal);
  box-shadow: 0 0 0 2px rgba(255, 106, 43, 0.22);
}

.idx-filter__label {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.idx-filter__key {
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 15px;
  padding: 0 4px;
  color: var(--signal);
  border: 1px solid rgba(255, 106, 43, 0.5);
  border-radius: 2px;
}

.idx-filter__input {
  width: clamp(92px, 12vw, 150px);
  padding: 0;
  border: 0;
  outline: none;
  background: transparent;
  color: var(--paper);
  font-family: var(--font-ui);
  font-size: 12.5px;
  line-height: 1.6;
}

.idx-filter__input::placeholder { color: rgba(154, 167, 180, 0.9); }

.idx-filter__input::-webkit-search-cancel-button {
  filter: invert(1) opacity(0.5);
}

.cmd__cta { flex: 0 0 auto; }

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 7px;
  height: 28px;
  padding: 0 9px;
  background: var(--ink-2);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  color: var(--paper);
  font-family: var(--font-ui);
  font-size: 12.5px;
  transition: border-color var(--step), color var(--step);
}

.nav-toggle:hover { border-color: var(--signal); color: var(--signal); }

.nav-toggle__bars {
  display: grid;
  gap: 3px;
  width: 14px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  background: currentColor;
  transition: transform var(--step), opacity var(--step);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}

/* 索引快捷条 */
.quick {
  background: var(--ink-2);
  border-top: 1px solid var(--line);
}

.quick__inner {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: var(--rail-h);
  overflow-x: auto;
  overscroll-behavior-x: contain;
  scrollbar-width: none;
}

.quick__inner::-webkit-scrollbar { display: none; }

.quick__label {
  flex: 0 0 auto;
  padding-right: 10px;
  border-right: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  color: var(--signal);
}

.quick__list {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: 4px;
}

.quick__item { flex: 0 0 auto; }

.quick__link {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 8px;
  font-family: var(--font-ui);
  font-size: 12px;
  line-height: 1.6;
  color: rgba(244, 241, 232, 0.72);
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 2px;
  white-space: nowrap;
  transition: background var(--step), color var(--step),
    border-color var(--step);
}

.quick__link:hover {
  color: var(--paper);
  border-color: var(--line-strong);
  background: rgba(255, 106, 43, 0.1);
}

.quick__no {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.04em;
  color: var(--rock);
  transition: color var(--step);
}

.quick__link:hover .quick__no { color: var(--signal); }

.quick__empty {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--clay);
}

/* 阅读进度 */
.read-meter {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: rgba(154, 167, 180, 0.18);
  pointer-events: none;
}

.read-meter__bar {
  display: block;
  width: 0;
  height: 100%;
  background: var(--signal);
  transition: width 120ms linear;
}

/* ============================================================
   13. 页脚
   ============================================================ */
.site-foot {
  background: var(--ink);
  border-top: 1px solid var(--line-strong);
  color: var(--paper);
}

.foot__grid {
  display: grid;
  grid-template-columns: 1.15fr 1.1fr 1.1fr 0.85fr;
  gap: clamp(22px, 3vw, 42px);
  padding-block: clamp(34px, 5vw, 58px) clamp(24px, 3vw, 34px);
}

.foot__col { min-width: 0; }

.foot__title {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-head);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--paper);
}

.foot__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

.foot__links {
  display: grid;
  gap: 2px;
}

.foot__links--tight { gap: 0; }

.foot__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 0;
  font-family: var(--font-ui);
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(244, 241, 232, 0.76);
  text-decoration: none;
  transition: color var(--step), padding var(--step);
}

.foot__link:hover {
  color: var(--signal);
  padding-left: 4px;
}

.foot__sub {
  margin: 16px 0 6px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: var(--rock);
}

.foot__label {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--rock);
}

.lookup {
  display: flex;
  gap: 6px;
}

.lookup__input {
  flex: 1 1 auto;
  min-width: 0;
  height: 30px;
  padding: 0 9px;
  background: var(--ink-2);
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  outline: none;
  transition: border-color var(--step), box-shadow var(--step);
}

.lookup__input::placeholder {
  color: rgba(154, 167, 180, 0.8);
  letter-spacing: 0.04em;
}

.lookup__input:focus {
  border-color: var(--signal);
  box-shadow: 0 0 0 2px rgba(255, 106, 43, 0.22);
}

.lookup__hint {
  margin-top: 8px;
  font-family: var(--font-ui);
  font-size: 12px;
  line-height: 1.7;
  color: var(--rock);
}

.lookup__hint[data-state="ok"] { color: #A7C0AF; }
.lookup__hint[data-state="warn"] { color: var(--clay); }

.foot__entry {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 14px;
  padding: 5px 10px 5px 0;
  border-bottom: 1px solid var(--line-strong);
  font-family: var(--font-ui);
  font-size: 13px;
  color: var(--paper);
  text-decoration: none;
  transition: color var(--step), border-color var(--step);
}

.foot__entry:hover {
  color: var(--signal);
  border-bottom-color: var(--signal);
}

.foot__arrow {
  font-family: var(--font-mono);
  color: var(--signal);
  transition: transform var(--step);
}

.foot__entry:hover .foot__arrow { transform: translateX(3px); }

.foot__list {
  display: grid;
  gap: 6px;
  font-family: var(--font-ui);
  font-size: 13px;
  line-height: 1.7;
  color: rgba(244, 241, 232, 0.8);
  word-break: break-word;
}

.foot__mono {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--signal-soft);
  word-break: break-all;
}

.foot__mono--muted {
  margin-top: 14px;
  color: var(--rock);
  letter-spacing: 0.06em;
}

.foot__note {
  margin-top: 12px;
  font-family: var(--font-ui);
  font-size: 12px;
  line-height: 1.75;
  color: var(--rock);
}

.foot__base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 20px;
  padding-block: 14px 26px;
  border-top: 1px solid var(--line);
}

.foot__stamp {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--rock);
}

.site-foot .mono {
  background: transparent;
  border-color: var(--line-strong);
  color: var(--signal-soft);
  font-size: 11.5px;
  padding: 1px 5px;
}

/* ============================================================
   14. 响应式
   ============================================================ */
@media (max-width: 1080px) {
  .idx-filter { display: none; }
  .nav__link { font-size: 13px; padding: 6px 7px; }
}

@media (max-width: 960px) {
  .nav-toggle { display: inline-flex; }

  .nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    z-index: 90;
    background: var(--ink);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line-strong);
    box-shadow: 0 24px 34px -26px rgba(0, 0, 0, 0.9);
    max-height: calc(100vh - var(--head-h));
    overflow-y: auto;
  }

  .nav[data-open] { display: block; }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 6px var(--gutter) 12px;
  }

  .nav__link {
    padding: 12px 10px;
    border: 0;
    border-bottom: 1px solid var(--line);
    border-radius: 0;
    font-size: 15px;
    color: rgba(244, 241, 232, 0.86);
  }

  .nav__link:hover { background: var(--ink-2); }

  .nav__link[aria-current="page"] {
    background: rgba(255, 106, 43, 0.14);
    color: var(--paper);
    box-shadow: inset 3px 0 0 var(--signal);
  }

  .brand__tagline { display: none; }

  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .foot__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 860px) {
  .grid--split { grid-template-columns: minmax(0, 1fr); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 720px) {
  body { font-size: 16.5px; }
  p { font-size: 16.5px; }
  .prose { font-size: 16.5px; }

  .quick__label { display: none; }
  .quick__inner { gap: 6px; }

  .cmd__cta { display: none; }

  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: minmax(0, 1fr); }

  .plate::before { inset: 4px; }

  .sheet--stack::after { inset: 6px -6px -6px 6px; }
}

@media (max-width: 560px) {
  .brand__name { font-size: 15px; }
  .foot__grid { grid-template-columns: minmax(0, 1fr); }
  .foot__base { justify-content: flex-start; }
  .lookup { flex-wrap: wrap; }
  .lookup__input { flex-basis: 100%; }
  .nav-toggle__text { display: none; }
  .nav-toggle { padding: 0 8px; }
}

/* ---------- 15. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .sheet:hover { transform: none; }
  .foot__link:hover { padding-left: 0; }
  .foot__entry:hover .foot__arrow { transform: none; }
  .skip-link { transition: none; }
}