/* ==========================================================================
   米官方主页 · 共享样式表 /assets/site.css
   精密仪器 + 档案室：粗边框、硬阴影、无圆角、等宽数字、分区色带
   ========================================================================== */

/* ---------- 1. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body, h1, h2, h3, h4, h5, p, ul, ol, li, dl, dt, dd, figure, blockquote, table { margin: 0; padding: 0; }
ul, ol { list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; }
hr { border: 0; height: 0; }

/* ---------- 2. 变量 ---------- */
:root {
  --paper:        #F7F4ED;
  --grid:         #E9E5DB;
  --archive:      #C6C0B2;
  --ink:          #12151A;
  --graphite:     #3B4048;
  --gold:         #B9822B;
  --gold-lite:    #E3C77E;
  --celadon:      #47756A;
  --celadon-lite: #A7C3B7;
  --slate:        #52698A;
  --slate-lite:   #AFC0D3;
  --revise:       #9E3B21;

  --font-head: "Noto Sans SC Condensed", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: Inter, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --bw: 1.5px;
  --bw-strong: 2px;
  --shadow: 4px 8px 0 var(--ink);
  --shadow-sm: 2px 4px 0 var(--ink);

  --shell: 1360px;
  --gutter: clamp(16px, 4vw, 48px);
  --ease: cubic-bezier(.2, .7, .3, 1);
  --dur: 180ms;
}

/* ---------- 3. 基底与中文排版 ---------- */
body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 120px 120px;
  background-position: -1px -1px;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: .005em;
}
body.is-nav-open { overflow: hidden; }

h1, h2, h3, h4 { font-family: var(--font-head); font-weight: 300; line-height: 1.16; letter-spacing: .01em; }
h1 { font-size: clamp(40px, 7vw, 96px); }
h2 { font-size: clamp(26px, 3.6vw, 44px); }
h3 { font-size: clamp(20px, 2.2vw, 28px); font-weight: 500; }
h4 { font-size: clamp(16px, 1.6vw, 20px); font-weight: 500; }
p { margin-bottom: 1em; }
p:last-child { margin-bottom: 0; }

.mono, .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}
.display {
  font-family: var(--font-head);
  font-weight: 300;
  font-size: clamp(44px, 9vw, 120px);
  line-height: .98;
  letter-spacing: -.01em;
  text-wrap: balance;
}
.lede { font-size: clamp(15px, 1.4vw, 19px); line-height: 1.7; color: var(--graphite); max-width: 64ch; }

/* ---------- 4. 骨架 ---------- */
.shell { width: min(100% - (var(--gutter) * 2), var(--shell)); margin-inline: auto; }
.page-main { display: block; }
#main-content:focus-visible { outline: var(--bw-strong) solid var(--slate); outline-offset: -2px; }

.skip-link {
  position: fixed;
  left: 12px;
  top: 0;
  z-index: 200;
  transform: translateY(-160%);
  background: var(--ink);
  color: var(--paper);
  border: var(--bw-strong) solid var(--gold);
  padding: 10px 18px;
  font-size: 13px;
  letter-spacing: .08em;
  transition: transform var(--dur) var(--ease);
}
.skip-link:focus { transform: translateY(10px); }

:focus-visible { outline: var(--bw-strong) solid var(--slate); outline-offset: 2px; }

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  border: var(--bw-strong) solid var(--ink);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: .06em;
  white-space: nowrap;
  box-shadow: var(--shadow-sm);
  transition: transform var(--dur) var(--ease), box-shadow var(--dur) var(--ease),
              background-color var(--dur) var(--ease), color var(--dur) var(--ease);
}
.btn:hover { transform: translate(2px, 4px); box-shadow: 0 0 0 var(--ink); background: var(--gold-lite); }
.btn:active { transform: translate(4px, 8px); box-shadow: 0 0 0 var(--ink); }
.btn--solid, .btn-solid { background: var(--ink); color: var(--paper); }
.btn--solid:hover, .btn-solid:hover { background: var(--gold); color: var(--ink); }
.btn--ghost { background: transparent; box-shadow: none; }
.btn--ghost:hover { background: var(--gold-lite); box-shadow: none; transform: translate(0, -2px); }
.btn--wide { width: 100%; }

/* ---------- 6. 页头：左右分置档案标签条 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--paper);
  border-bottom: var(--bw) solid var(--ink);
}
.header-grid {
  display: grid;
  grid-template-columns: minmax(0, auto) 2px minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(14px, 2.2vw, 34px);
  min-height: 88px;
  padding-block: 8px;
  transition: min-height var(--dur) var(--ease);
}
.site-header[data-condensed="true"] { border-bottom-width: var(--bw-strong); }
.site-header[data-condensed="true"] .header-grid { min-height: 62px; }
.site-header[data-condensed="true"] .brand-scope { max-height: 0; opacity: 0; }

/* 品牌区块 */
.header-brand { display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.brand-link { display: flex; align-items: baseline; gap: 10px; }
.brand-title {
  font-family: var(--font-head);
  font-size: 22px;
  font-weight: 500;
  letter-spacing: .08em;
  white-space: nowrap;
  transition: box-shadow var(--dur) var(--ease);
}
.brand-link:hover .brand-title { box-shadow: inset 0 -6px 0 var(--gold-lite); }
.brand-rev {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--gold);
  border: var(--bw) solid var(--gold);
  padding: 1px 6px;
  white-space: nowrap;
}
.brand-scope {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: .06em;
  color: var(--graphite);
  max-height: 22px;
  overflow: hidden;
  transition: max-height var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

/* 中间竖线与站标 */
.header-rule {
  align-self: stretch;
  margin-block: 12px;
  width: 2px;
  background: var(--ink);
  position: relative;
}
.rule-tag {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  writing-mode: vertical-rl;
  background: var(--paper);
  color: var(--graphite);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .22em;
  padding: 6px 2px;
}

/* 栏目区块 */
.site-nav { display: flex; align-items: center; justify-content: flex-end; min-width: 0; }
.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: clamp(2px, .9vw, 12px);
  counter-reset: navindex;
}
.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 8px 10px;
  font-size: 14px;
  letter-spacing: .04em;
  color: var(--graphite);
  border: var(--bw) solid transparent;
  transition: color var(--dur) var(--ease), background-color var(--dur) var(--ease),
              border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.nav-link::before {
  counter-increment: navindex;
  content: "0" counter(navindex);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .04em;
  color: var(--archive);
  transition: color var(--dur) var(--ease);
}
.nav-link:hover { color: var(--ink); background: var(--grid); border-color: var(--ink); }
.nav-link:hover::before { color: var(--gold); }
.nav-link[aria-current="page"] {
  color: var(--ink);
  font-weight: 600;
  background: rgba(227, 199, 126, .3);
  border-color: var(--ink);
  box-shadow: inset 0 -3px 0 var(--gold);
}
.nav-link[aria-current="page"]::before { color: var(--gold); }

.header-cta { display: flex; align-items: center; }
.nav-foot { display: none; }
.nav-foot-row { font-family: var(--font-mono); font-size: 11px; letter-spacing: .12em; color: var(--graphite); margin: 0; }

/* 阅读进度线 */
.scroll-rule {
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 2px;
  background: var(--gold);
  transform: scaleX(0);
  transform-origin: 0 50%;
  will-change: transform;
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 9px 12px;
  border: var(--bw-strong) solid var(--ink);
  background: var(--paper);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--ink);
  box-shadow: var(--shadow-sm);
  transition: background-color var(--dur) var(--ease), transform var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
}
.nav-toggle:hover { background: var(--gold-lite); }
.nav-toggle:active { transform: translate(2px, 4px); box-shadow: 0 0 0 var(--ink); }
.nav-toggle-mark { position: relative; display: block; width: 18px; height: 2px; background: var(--ink); }
.nav-toggle-mark::before,
.nav-toggle-mark::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: var(--ink);
  transition: transform var(--dur) var(--ease), top var(--dur) var(--ease);
}
.nav-toggle-mark::before { top: -6px; }
.nav-toggle-mark::after { top: 6px; }
.site-header[data-open="true"] .nav-toggle-mark { background: transparent; }
.site-header[data-open="true"] .nav-toggle-mark::before { top: 0; transform: rotate(45deg); }
.site-header[data-open="true"] .nav-toggle-mark::after { top: 0; transform: rotate(-45deg); }

/* ---------- 7. 页脚：墨黑横向信息带 ---------- */
.site-footer {
  margin-top: auto;
  background: var(--ink);
  color: rgba(247, 244, 237, .84);
  border-top: var(--bw-strong) solid var(--gold);
  font-size: 13px;
  line-height: 1.7;
}
.footer-band {
  display: grid;
  grid-template-columns: 1.1fr 1fr .8fr 1.4fr;
  gap: 0;
  padding-block: 44px 36px;
}
.footer-col { padding-inline: clamp(12px, 1.8vw, 28px); border-left: var(--bw) solid rgba(247, 244, 237, .18); }
.footer-col:first-child { padding-left: 0; border-left: 0; }
.footer-head {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .2em;
  color: var(--gold-lite);
  margin-bottom: 14px;
}
.footer-head::after { content: ""; display: block; width: 24px; height: 2px; background: var(--gold); margin-top: 8px; }
.footer-list li { margin-bottom: 6px; }
.footer-list a { border-bottom: var(--bw) solid transparent; transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease); }
.footer-list a:hover { color: var(--gold-lite); border-bottom-color: var(--gold-lite); }
.footer-static { color: rgba(247, 244, 237, .72); }

.contact-list dt {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  color: rgba(247, 244, 237, .5);
  margin-top: 12px;
}
.contact-list dt:first-child { margin-top: 0; }
.contact-list dd { color: var(--paper); margin-bottom: 4px; word-break: break-word; }
.contact-address { color: rgba(247, 244, 237, .9); }
.contact-note { margin-top: 16px; font-size: 12px; line-height: 1.7; color: rgba(247, 244, 237, .58); }

.copy-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 2px 7px;
  border: var(--bw) dashed currentColor;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .02em;
  color: var(--paper);
  word-break: break-all;
  text-align: left;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease),
              border-color var(--dur) var(--ease);
}
.copy-chip::after {
  content: "复制";
  font-family: var(--font-body);
  font-size: 10px;
  letter-spacing: .1em;
  opacity: .6;
  white-space: nowrap;
}
.copy-chip:hover { background: var(--gold); color: var(--ink); border-style: solid; border-color: var(--gold); }
.copy-chip[data-copied="true"] { background: var(--celadon); color: var(--paper); border-style: solid; border-color: var(--celadon); }
.copy-chip[data-copied="true"]::after { content: "已复制"; opacity: 1; }

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 32px;
  padding-block: 18px 26px;
  border-top: var(--bw) solid rgba(247, 244, 237, .22);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: rgba(247, 244, 237, .6);
}
.footer-brand { display: flex; align-items: center; gap: 10px; margin: 0; color: var(--paper); letter-spacing: .14em; }
.footer-brand::before { content: ""; width: 10px; height: 10px; background: var(--gold); }
.footer-meta { display: flex; flex-wrap: wrap; gap: 8px 26px; margin: 0; }
.footer-icp { color: rgba(247, 244, 237, .72); }

/* ---------- 8. 面包屑 / 章节 / 索引标签 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 14px;
  border-bottom: var(--bw) solid var(--grid);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--graphite);
}
.breadcrumb a { transition: color var(--dur) var(--ease), box-shadow var(--dur) var(--ease); }
.breadcrumb a:hover { color: var(--ink); box-shadow: inset 0 -2px 0 var(--gold); }
.breadcrumb-sep { color: var(--archive); }
.breadcrumb [aria-current="page"] { color: var(--ink); }

.section { padding-block: clamp(38px, 6vw, 88px); border-bottom: var(--bw) solid var(--grid); }
.section:last-child { border-bottom: 0; }
.section--tight { padding-block: clamp(24px, 3.4vw, 48px); }
.section--ink { background: var(--ink); color: var(--paper); border-bottom-color: var(--ink); }
.section--grid { background: rgba(233, 229, 219, .55); }

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px 32px;
  padding-bottom: 18px;
  margin-bottom: clamp(22px, 3vw, 38px);
  border-bottom: var(--bw-strong) solid var(--ink);
}
.section-index {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .2em;
  color: var(--gold);
}
.section-title { font-size: clamp(24px, 3vw, 40px); font-weight: 300; margin: 0; }
.section-note { font-family: var(--font-mono); font-size: 11.5px; letter-spacing: .1em; color: var(--graphite); margin: 0; }

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .22em;
  color: var(--gold);
}
.eyebrow::before { content: ""; width: 28px; height: 2px; background: currentColor; }

.rule-h { height: var(--bw-strong); background: var(--ink); border: 0; }

/* ---------- 9. 布局工具 ---------- */
.grid { display: grid; gap: clamp(16px, 2.2vw, 28px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.grid--auto { grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); }

.split { display: grid; gap: clamp(20px, 3vw, 44px); }
.split--4-8 { grid-template-columns: minmax(0, 4fr) minmax(0, 8fr); }
.split--3-9 { grid-template-columns: minmax(0, 3fr) minmax(0, 9fr); }
.split--5-7 { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }
.split--divider > * + * { border-left: var(--bw) solid var(--grid); padding-left: clamp(20px, 3vw, 44px); }

/* ---------- 10. 面板 / 标签 ---------- */
.panel {
  border: var(--bw-strong) solid var(--ink);
  background: var(--paper);
  box-shadow: var(--shadow);
  padding: clamp(18px, 2.4vw, 30px);
}
.panel-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px 16px;
  padding-bottom: 12px;
  margin-bottom: 16px;
  border-bottom: var(--bw) solid var(--ink);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--graphite);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  border: var(--bw) solid currentColor;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  line-height: 1.4;
}
.tag--gold { color: var(--gold); background: rgba(227, 199, 126, .24); }
.tag--celadon { color: var(--celadon); background: rgba(167, 195, 183, .32); }
.tag--slate { color: var(--slate); background: rgba(175, 192, 211, .3); }
.tag--revise { color: var(--revise); background: rgba(158, 59, 33, .12); }

/* ---------- 11. 数据表 ---------- */
.spec-table-wrap {
  border: var(--bw-strong) solid var(--ink);
  background: var(--paper);
  box-shadow: var(--shadow);
  overflow-x: auto;
}
.spec-table { width: 100%; min-width: 520px; font-size: 13.5px; }
.spec-table caption {
  caption-side: top;
  text-align: left;
  padding: 12px 14px;
  border-bottom: var(--bw) solid var(--ink);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--graphite);
}
.spec-table th, .spec-table td { padding: 11px 14px; text-align: left; vertical-align: top; border-bottom: var(--bw) solid var(--grid); }
.spec-table thead th {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: .12em;
  border-bottom: var(--bw-strong) solid var(--ink);
}
.spec-table tbody tr:nth-child(even) { background: var(--grid); }
.spec-table tbody tr { transition: background-color var(--dur) var(--ease); }
.spec-table tbody tr:hover { background: rgba(227, 199, 126, .38); }
.spec-table tbody tr:last-child th, .spec-table tbody tr:last-child td { border-bottom: 0; }
.spec-table .num, .spec-table td.num { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

/* ---------- 12. 密集索引列表 ---------- */
.list-index { border-top: var(--bw-strong) solid var(--ink); }
.list-index li { border-bottom: var(--bw) solid var(--grid); }
.list-index a, .list-index .list-row {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr) auto;
  gap: 12px 18px;
  align-items: baseline;
  padding: 13px 6px;
  transition: background-color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}
.list-index a:hover, .list-index .list-row:hover { background: var(--grid); padding-left: 16px; }
.list-index .idx { font-family: var(--font-mono); font-size: 11px; letter-spacing: .12em; color: var(--gold); }
.list-index .meta { font-family: var(--font-mono); font-size: 11.5px; letter-spacing: .06em; color: var(--graphite); }

/* ---------- 13. 图片容器与主题视觉 ---------- */
.frame {
  position: relative;
  display: block;
  min-height: 160px;
  border: var(--bw-strong) solid var(--ink);
  background-color: var(--grid);
  background-image:
    linear-gradient(rgba(198, 192, 178, .55) 1px, transparent 1px),
    linear-gradient(90deg, rgba(198, 192, 178, .55) 1px, transparent 1px);
  background-size: 48px 48px;
  box-shadow: var(--shadow);
  overflow: hidden;
}
.frame > img, .frame > picture > img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; }
.frame--wide > img, .frame--wide > picture > img { aspect-ratio: 16 / 9; }
.frame--tall > img, .frame--tall > picture > img { aspect-ratio: 3 / 4; }
.frame--square > img, .frame--square > picture > img { aspect-ratio: 1 / 1; }
.frame-tag {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 3;
  padding: 4px 10px;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .14em;
}
.frame-cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--graphite);
}
.grad-field {
  background-color: var(--grid);
  background-image:
    radial-gradient(120% 90% at 12% 8%, rgba(227, 199, 126, .62), transparent 62%),
    radial-gradient(100% 80% at 88% 24%, rgba(167, 195, 183, .55), transparent 64%),
    radial-gradient(120% 100% at 50% 100%, rgba(175, 192, 211, .5), transparent 62%);
}

/* ---------- 14. 首屏基础原语 ---------- */
.hero { border-bottom: var(--bw-strong) solid var(--ink); }
.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: 0;
  align-items: stretch;
}
.hero-narrative { padding-block: clamp(32px, 5vw, 72px); padding-right: clamp(20px, 3vw, 44px); }
.hero-visual {
  position: relative;
  border-left: var(--bw-strong) solid var(--ink);
  padding: clamp(20px, 3vw, 44px);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 260px;
}
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  padding-top: 20px;
  margin-top: 24px;
  border-top: var(--bw) solid var(--grid);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--graphite);
}

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1180px) {
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-band { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 32px 0; }
  .footer-col:nth-child(3) { padding-left: 0; border-left: 0; }
}

@media (max-width: 1023px) {
  .header-grid {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 12px;
    min-height: 66px;
    padding-block: 10px;
  }
  .header-rule, .header-cta { display: none; }
  .brand-scope { display: none; }
  .nav-toggle { display: inline-flex; }
  .site-header[data-condensed="true"] .header-grid { min-height: 66px; }

  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    max-height: calc(100vh - 100%);
    overflow-y: auto;
    padding: 6px var(--gutter) 26px;
    background: var(--paper);
    border-bottom: var(--bw-strong) solid var(--ink);
  }
  .site-header[data-open="true"] .site-nav { display: flex; }
  .nav-list { flex-direction: column; align-items: stretch; gap: 0; counter-reset: navindex; }
  .nav-link {
    width: 100%;
    justify-content: flex-start;
    padding: 15px 2px;
    border: 0;
    border-bottom: var(--bw) solid var(--grid);
    box-shadow: none;
  }
  .nav-link:hover { background: var(--grid); border-color: var(--grid); padding-left: 12px; }
  .nav-link[aria-current="page"] { background: rgba(227, 199, 126, .3); box-shadow: inset 4px 0 0 var(--gold); padding-left: 12px; }
  .nav-foot { display: flex; flex-direction: column; align-items: flex-start; gap: 14px; padding-top: 22px; }

  .split--4-8, .split--3-9, .split--5-7, .hero-grid { grid-template-columns: minmax(0, 1fr); }
  .split--divider > * + * { border-left: 0; padding-left: 0; border-top: var(--bw) solid var(--grid); padding-top: 24px; }
  .hero-narrative { padding-right: 0; }
  .hero-visual { border-left: 0; border-top: var(--bw-strong) solid var(--ink); }
}

@media (max-width: 720px) {
  .grid--2, .grid--3, .grid--4, .grid--auto { grid-template-columns: minmax(0, 1fr); }
  .footer-band { grid-template-columns: minmax(0, 1fr); gap: 30px 0; }
  .footer-col { padding-inline: 0; border-left: 0; }
  .footer-col + .footer-col { border-top: var(--bw) solid rgba(247, 244, 237, .18); padding-top: 24px; }
  .footer-base { justify-content: flex-start; }
  .list-index a, .list-index .list-row { grid-template-columns: 42px minmax(0, 1fr); }
  .list-index .meta { grid-column: 2; }
  .brand-title { font-size: 19px; }
}

/* ---------- 16. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    transition-delay: 0ms !important;
  }
  .scroll-rule { display: none; }
}