/* =====================================================================
   金宝搏注册 · 共享样式表  /assets/site.css
   含 reset、设计令牌、中文排版、页头页脚、通用组件与图片容器
   ===================================================================== */

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

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

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

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

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

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

a { color: inherit; }

/* ---------- 2. 设计令牌 ---------- */
:root {
  --gold: #B8873B;
  --gold-light: #D9B36C;
  --ink: #12263A;
  --sand: #E8DCC8;
  --ivory: #F7F2E8;
  --cinnabar: #C8402A;
  --verdigris: #3E6B5E;
  --indigo: #2E2A4F;
  --wine: #6E2430;
  --graphite: #3A3A38;

  --line: rgba(184, 135, 59, .38);
  --line-soft: rgba(18, 38, 58, .14);
  --line-invert: rgba(217, 179, 108, .32);

  --wrap: 1180px;
  --gutter: clamp(1.1rem, 4vw, 2.4rem);
  --radius: 3px;

  --serif: "Songti SC", "STSong", "Source Han Serif SC", "Noto Serif SC", "SimSun", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, "Courier New", monospace;

  --shadow-plate: inset 0 1px 0 rgba(247, 242, 232, .65), 0 18px 40px -30px rgba(18, 38, 58, .6);
}

html { scroll-behavior: smooth; }

/* ---------- 3. 基础排版（中文语境） ---------- */
body {
  min-height: 100vh;
  background: var(--ivory);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: .01em;
}

h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: .02em;
  color: var(--ink);
}

h1 { font-size: clamp(2rem, 4.6vw, 2.9rem); letter-spacing: .04em; }
h2 { font-size: clamp(1.5rem, 3vw, 2.1rem); }
h3 { font-size: clamp(1.15rem, 2vw, 1.45rem); }
h4 { font-size: 1.05rem; }

p { margin-bottom: 1.05em; }

p:last-child { margin-bottom: 0; }

strong { font-weight: 700; }

.mono {
  font-family: var(--mono);
  font-size: .78em;
  letter-spacing: .18em;
  text-transform: uppercase;
}

/* ---------- 4. 基础工具类 ---------- */
.wrap {
  width: min(calc(100% - var(--gutter) * 2), var(--wrap));
  margin-inline: auto;
}

.skip-link {
  position: absolute;
  top: -4.5rem;
  left: 50%;
  z-index: 300;
  transform: translateX(-50%);
  padding: .7rem 1.3rem;
  background: var(--ink);
  color: var(--ivory);
  border: 1px solid var(--gold-light);
  border-radius: var(--radius);
  font-size: .85rem;
  letter-spacing: .12em;
  text-decoration: none;
  transition: top .2s ease;
}

.skip-link:focus { top: .7rem; }

#main-content { display: block; scroll-margin-top: 96px; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .65rem;
  color: var(--gold);
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .28em;
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";
  width: 34px;
  height: 1px;
  background: currentColor;
  opacity: .8;
}

.divider {
  height: 1px;
  margin: clamp(1.6rem, 4vw, 2.6rem) 0;
  border: 0;
  background: linear-gradient(90deg, var(--gold), rgba(184, 135, 59, 0));
}

/* ---------- 5. 页头 · 居中刊头 ---------- */
.site-header {
  position: relative;
  background: var(--ivory);
}

.site-header::before {
  content: "";
  display: block;
  height: 4px;
  background: linear-gradient(90deg, transparent 0%, var(--gold) 16%, var(--gold-light) 50%, var(--gold) 84%, transparent 100%);
}

.site-header__masthead {
  background:
    radial-gradient(120% 170% at 50% -50%, rgba(217, 179, 108, .22), transparent 62%),
    var(--ivory);
  border-bottom: 1px solid var(--line-soft);
}

.masthead {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1.2rem;
  padding: 1.6rem 0 1.2rem;
}

.masthead__aside {
  margin: 0;
  color: var(--graphite);
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .14em;
}

.masthead__aside--right { text-align: right; }

.brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0 .5rem;
  color: var(--ink);
  text-decoration: none;
}

.brand__zh {
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(1.5rem, 3.6vw, 2.35rem);
  line-height: 1.12;
  letter-spacing: .24em;
  text-indent: .24em;
  transition: color .2s ease;
}

.brand__py,
.brand__en {
  font-family: var(--mono);
  font-size: .62rem;
  text-transform: uppercase;
  color: var(--gold);
}

.brand__py { margin-top: .35rem; letter-spacing: .46em; text-indent: .46em; }

.brand__en { margin-top: .12rem; letter-spacing: .26em; text-indent: .26em; color: rgba(58, 58, 56, .62); }

.brand::after {
  content: "";
  width: 78px;
  height: 1px;
  margin-top: .7rem;
  background: linear-gradient(90deg, transparent, var(--gold), transparent);
  transition: background .2s ease;
}

.brand:hover .brand__zh { color: var(--indigo); }

.brand:hover::after { background: linear-gradient(90deg, transparent, var(--gold-light), transparent); }

/* 深墨蓝导航带（粘性，承载章节目录） */
.site-header__bar {
  position: sticky;
  top: 0;
  z-index: 120;
  background: var(--ink);
  border-bottom: 1px solid var(--line-invert);
  box-shadow: 0 14px 30px -26px rgba(18, 38, 58, .95);
}

.site-header__bar::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--gold) 28%, var(--gold-light) 50%, var(--gold) 72%, transparent);
}

.site-nav__wrap {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  min-height: 54px;
}

.site-nav__list {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: .15rem;
}

.site-nav__link {
  display: inline-block;
  padding: .5rem .85rem;
  color: rgba(232, 220, 200, .82);
  border-bottom: 2px solid transparent;
  font-size: .9rem;
  letter-spacing: .14em;
  text-decoration: none;
  transition: color .18s ease, border-color .18s ease, background-color .18s ease;
}

.site-nav__link:hover {
  color: var(--gold-light);
  border-bottom-color: var(--gold-light);
}

.site-nav__link[aria-current="page"] {
  color: var(--ivory);
  border-bottom-color: var(--cinnabar);
}

.site-nav__cta {
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  display: inline-flex;
  align-items: center;
  padding: .42rem .95rem;
  color: var(--gold-light);
  border: 1px solid var(--gold);
  border-radius: var(--radius);
  font-size: .78rem;
  letter-spacing: .16em;
  white-space: nowrap;
  text-decoration: none;
  transition: background-color .2s ease, color .2s ease;
}

.site-nav__cta:hover { background: var(--gold); color: var(--ink); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: .55rem;
  padding: .45rem .8rem;
  background: transparent;
  color: var(--sand);
  border: 1px solid var(--line-invert);
  border-radius: var(--radius);
  cursor: pointer;
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .22em;
  text-transform: uppercase;
  transition: border-color .2s ease, color .2s ease;
}

.nav-toggle__bars {
  display: inline-block;
  width: 15px;
  height: 2px;
  background: var(--gold-light);
  box-shadow: 0 5px 0 var(--gold-light), 0 -5px 0 var(--gold-light);
}

.nav-toggle[aria-expanded="true"] {
  color: var(--ivory);
  border-color: var(--gold-light);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars {
  background: var(--cinnabar);
  box-shadow: 0 5px 0 var(--gold-light), 0 -5px 0 var(--gold-light);
}

/* ---------- 6. 章节目录条 ---------- */
.chapter-bar {
  background: linear-gradient(90deg, rgba(184, 135, 59, .16), transparent 45%);
  border-top: 1px dashed var(--line-invert);
}

.chapter-bar[hidden] { display: none; }

.chapter-bar__inner {
  display: flex;
  align-items: center;
  gap: .9rem;
  padding: .34rem 0 .44rem;
}

.chapter-bar__label {
  flex: 0 0 auto;
  color: var(--gold-light);
  font-size: .66rem;
  letter-spacing: .3em;
}

.chapter-nav {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.chapter-nav__list {
  display: flex;
  align-items: center;
  gap: .3rem;
}

.chapter-nav__link {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  padding: .28rem .6rem;
  white-space: nowrap;
  color: rgba(232, 220, 200, .7);
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-size: .78rem;
  letter-spacing: .06em;
  text-decoration: none;
  transition: color .18s ease, border-color .18s ease, background-color .18s ease;
}

.chapter-nav__num {
  font-family: var(--mono);
  font-size: .66rem;
  letter-spacing: .1em;
  color: var(--gold);
}

.chapter-nav__link:hover {
  color: var(--ivory);
  border-color: var(--line-invert);
}

.chapter-nav__link[aria-current="true"] {
  color: var(--ivory);
  border-color: var(--gold);
  background: rgba(184, 135, 59, .18);
}

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .68rem 1.35rem;
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--gold);
  border-radius: var(--radius);
  font-size: .9rem;
  letter-spacing: .14em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color .2s ease, color .2s ease, border-color .2s ease;
}

.btn--gold { background: var(--gold); color: var(--ivory); }
.btn--gold:hover { background: var(--gold-light); color: var(--ink); }

.btn--outline { color: var(--gold); }
.btn--outline:hover { background: var(--gold); color: var(--ivory); }

.btn--ink { background: var(--ink); color: var(--ivory); border-color: var(--ink); }
.btn--ink:hover { background: var(--indigo); border-color: var(--indigo); }

.btn--red { background: var(--cinnabar); color: var(--ivory); border-color: var(--cinnabar); }
.btn--red:hover { background: #d24b33; border-color: #d24b33; }

/* ---------- 8. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .55rem;
  padding: .95rem 0;
  color: var(--graphite);
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .14em;
}

.breadcrumb__link {
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .18s ease, border-color .18s ease;
}

.breadcrumb__link:hover { color: var(--gold); border-bottom-color: var(--gold); }

.breadcrumb__sep { color: var(--gold); }

/* ---------- 9. 分区与 Bento 网格 ---------- */
.section { padding: clamp(2.4rem, 6vw, 4.6rem) 0; }

.section--sand { background: var(--sand); }
.section--ivory { background: var(--ivory); }
.section--ink { background: var(--ink); color: var(--sand); }
.section--verdigris { background: var(--verdigris); color: var(--ivory); }
.section--indigo { background: var(--indigo); color: var(--sand); }
.section--wine { background: var(--wine); color: var(--ivory); }

.section--ink h1, .section--ink h2, .section--ink h3, .section--ink h4,
.section--indigo h1, .section--indigo h2, .section--indigo h3, .section--indigo h4,
.section--verdigris h1, .section--verdigris h2, .section--verdigris h3, .section--verdigris h4,
.section--wine h1, .section--wine h2, .section--wine h3, .section--wine h4 { color: var(--ivory); }

.section__head {
  display: grid;
  gap: .7rem;
  max-width: 62ch;
  margin-bottom: clamp(1.6rem, 3vw, 2.4rem);
}

.section__title { margin: 0; }

.lede {
  max-width: 64ch;
  color: var(--graphite);
  font-size: 1.04rem;
  line-height: 1.95;
}

.section--ink .lede,
.section--indigo .lede { color: rgba(232, 220, 200, .82); }

.section--verdigris .lede,
.section--wine .lede { color: rgba(247, 242, 232, .86); }

.grid {
  display: grid;
  gap: clamp(1rem, 2.4vw, 1.8rem);
}

.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--bento { grid-template-columns: repeat(12, minmax(0, 1fr)); }

.col-4 { grid-column: span 4; }
.col-5 { grid-column: span 5; }
.col-6 { grid-column: span 6; }
.col-7 { grid-column: span 7; }
.col-8 { grid-column: span 8; }
.col-12 { grid-column: span 12; }

/* ---------- 10. 档案卡、标签、编号 ---------- */
.card {
  position: relative;
  padding: clamp(1.1rem, 2.4vw, 1.6rem);
  background: var(--ivory);
  border: 1px solid var(--line-soft);
  border-top: 2px solid var(--gold);
  border-radius: var(--radius);
  box-shadow: var(--shadow-plate);
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--line);
  box-shadow: inset 0 1px 0 rgba(247, 242, 232, .65), 0 26px 46px -34px rgba(18, 38, 58, .75);
}

.card__title {
  margin-bottom: .5rem;
  font-family: var(--serif);
  font-size: 1.15rem;
}

.card__meta {
  color: var(--graphite);
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .2em;
  text-transform: uppercase;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .22rem .62rem;
  color: var(--gold);
  background: rgba(232, 220, 200, .55);
  border: 1px solid var(--line);
  border-radius: 999px;
  font-family: var(--mono);
  font-size: .66rem;
  letter-spacing: .18em;
  text-transform: uppercase;
}

.tag--red {
  color: var(--cinnabar);
  background: rgba(200, 64, 42, .08);
  border-color: rgba(200, 64, 42, .42);
}

.tag--verdigris {
  color: var(--verdigris);
  background: rgba(62, 107, 94, .1);
  border-color: rgba(62, 107, 94, .42);
}

.index-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  color: var(--gold-light);
  background: var(--ink);
  border: 1px solid var(--gold);
  border-radius: 50%;
  font-family: var(--mono);
  font-size: .76rem;
  letter-spacing: .04em;
}

.glass {
  background: rgba(247, 242, 232, .62);
  -webkit-backdrop-filter: blur(10px) saturate(1.2);
  backdrop-filter: blur(10px) saturate(1.2);
  border: 1px solid rgba(184, 135, 59, .32);
  border-radius: var(--radius);
}

/* ---------- 11. 图片容器基础规则 ---------- */
.frame {
  position: relative;
  display: block;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    linear-gradient(140deg, rgba(184, 135, 59, .32), rgba(18, 38, 58, .12) 55%, rgba(232, 220, 200, .75)),
    var(--sand);
}

.frame > img,
.frame__media {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.frame--16x9 { aspect-ratio: 16 / 9; }
.frame--4x3 { aspect-ratio: 4 / 3; }
.frame--3x4 { aspect-ratio: 3 / 4; }
.frame--1x1 { aspect-ratio: 1 / 1; }
.frame--wide { aspect-ratio: 21 / 9; }

.frame__cap {
  position: absolute;
  left: 0;
  bottom: 0;
  max-width: 100%;
  padding: .45rem .8rem;
  background: rgba(18, 38, 58, .82);
  color: var(--sand);
  font-size: .72rem;
  letter-spacing: .08em;
}

.frame__index {
  position: absolute;
  top: .6rem;
  right: .6rem;
  padding: .12rem .48rem;
  background: rgba(200, 64, 42, .92);
  color: var(--ivory);
  border-radius: 2px;
  font-family: var(--mono);
  font-size: .64rem;
  letter-spacing: .16em;
}

/* ---------- 12. 数据表 ---------- */
.table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  background: var(--ivory);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
}

table.data {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--mono);
  font-size: .82rem;
}

table.data th,
table.data td {
  padding: .62rem .9rem;
  text-align: left;
  white-space: nowrap;
  border-bottom: 1px solid var(--line-soft);
}

table.data thead th {
  background: var(--ink);
  color: var(--gold-light);
  font-size: .68rem;
  font-weight: 400;
  letter-spacing: .16em;
  text-transform: uppercase;
}

table.data tbody tr:nth-child(even) { background: rgba(232, 220, 200, .42); }

/* ---------- 13. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(2.5rem, 6vw, 5rem);
  color: var(--sand);
  background:
    radial-gradient(115% 105% at 88% 0%, rgba(46, 42, 79, .9), transparent 62%),
    var(--ink);
}

.site-footer::before {
  content: "";
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--gold), var(--gold-light) 45%, var(--gold));
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 1.55fr .9fr .85fr 1.6fr;
  gap: clamp(1.6rem, 4vw, 3rem);
  padding: clamp(2.2rem, 5vw, 3.4rem) 0 clamp(1.6rem, 4vw, 2.4rem);
}

.footer-brand__mark {
  display: inline-flex;
  flex-direction: column;
  text-decoration: none;
}

.footer-brand__zh {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: .2em;
  color: var(--ivory);
}

.footer-brand__py {
  margin-top: .3rem;
  color: var(--gold-light);
  font-family: var(--mono);
  font-size: .62rem;
  letter-spacing: .46em;
  text-transform: uppercase;
}

.footer-brand__en {
  margin-top: .55rem;
  color: rgba(232, 220, 200, .55);
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .24em;
  text-transform: uppercase;
}

.footer-brand__note {
  max-width: 28ch;
  margin-top: 1rem;
  color: rgba(232, 220, 200, .72);
  font-size: .85rem;
  line-height: 1.85;
}

.footer-col__title {
  margin-bottom: .9rem;
  color: var(--gold-light);
  font-family: var(--mono);
  font-size: .7rem;
  font-weight: 400;
  letter-spacing: .28em;
  text-transform: uppercase;
}

.footer-col__list { display: grid; gap: .5rem; }

.footer-col__link {
  display: inline-block;
  color: rgba(232, 220, 200, .84);
  border-bottom: 1px solid transparent;
  font-size: .92rem;
  letter-spacing: .04em;
  text-decoration: none;
  transition: color .18s ease, border-color .18s ease;
}

.footer-col__link:hover {
  color: var(--gold-light);
  border-bottom-color: var(--gold-light);
}

.footer-contact { display: grid; gap: .7rem; }

.footer-contact li {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: .6rem;
  align-items: baseline;
  font-size: .85rem;
}

.footer-contact__k {
  color: var(--gold-light);
  font-size: .64rem;
  letter-spacing: .2em;
}

.footer-contact__v {
  color: rgba(232, 220, 200, .86);
  line-height: 1.7;
  word-break: break-word;
}

.copy-btn {
  padding: .12rem .48rem;
  background: transparent;
  color: rgba(232, 220, 200, .68);
  border: 1px solid var(--line-invert);
  border-radius: 2px;
  cursor: pointer;
  font-size: .64rem;
  letter-spacing: .16em;
  transition: color .18s ease, border-color .18s ease, background-color .18s ease;
}

.copy-btn:hover { color: var(--ivory); border-color: var(--gold-light); }

.copy-btn[data-copied="true"] {
  color: var(--ivory);
  background: rgba(184, 135, 59, .3);
  border-color: var(--gold);
}

.site-footer__base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 0 1.5rem;
  border-top: 1px solid var(--line-invert);
  color: rgba(232, 220, 200, .64);
  font-size: .78rem;
}

.site-footer__copy,
.site-footer__icp { margin: 0; }

.site-footer__icp { letter-spacing: .16em; }

.to-top {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  padding: .42rem .9rem;
  background: transparent;
  color: var(--gold-light);
  border: 1px solid var(--line-invert);
  border-radius: var(--radius);
  cursor: pointer;
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .2em;
  transition: color .2s ease, border-color .2s ease, background-color .2s ease;
}

.to-top::after {
  content: "↑";
  font-size: .9rem;
  line-height: 1;
}

.to-top:hover { color: var(--ivory); border-color: var(--gold); }

.to-top[data-visible="true"] {
  color: var(--ivory);
  background: rgba(184, 135, 59, .22);
  border-color: var(--gold);
}

/* ---------- 14. 焦点可见性 ---------- */
:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 3px;
}

.site-header__bar :focus-visible,
.site-footer :focus-visible { outline-color: var(--gold-light); }

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1180px) {
  .site-nav__cta { display: none; }
}

@media (max-width: 960px) {
  .site-footer__grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 900px) {
  .nav-toggle { display: inline-flex; }

  .site-nav__wrap {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    min-height: 0;
    padding-top: .55rem;
    padding-bottom: .55rem;
  }

  .site-nav__list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: .3rem 0 0;
  }

  .site-nav[data-open] .site-nav__list { display: flex; }

  .site-nav__link {
    padding: .8rem .2rem;
    border-bottom: 1px solid rgba(247, 242, 232, .14);
    font-size: .98rem;
    letter-spacing: .1em;
  }

  .site-nav__link:hover {
    color: var(--gold-light);
    border-bottom-color: rgba(247, 242, 232, .14);
  }

  .site-nav__link[aria-current="page"] {
    color: var(--ivory);
    border-bottom-color: rgba(247, 242, 232, .14);
    border-left: 2px solid var(--cinnabar);
    background: rgba(200, 64, 42, .18);
    padding-left: .7rem;
  }

  .chapter-bar__inner {
    flex-direction: column;
    align-items: flex-start;
    gap: .25rem;
    padding-bottom: .6rem;
  }

  .chapter-nav { width: 100%; }

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

  .col-4, .col-5, .col-6, .col-7, .col-8 { grid-column: span 12; }
}

@media (max-width: 760px) {
  .masthead {
    grid-template-columns: 1fr;
    justify-items: center;
    gap: .45rem;
    padding: 1.15rem 0 .95rem;
  }

  .masthead__aside { display: none; }

  .brand__zh { letter-spacing: .18em; text-indent: .18em; }
}

@media (max-width: 620px) {
  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: 1fr; }

  .site-footer__grid { grid-template-columns: 1fr; }

  .footer-contact li { grid-template-columns: auto 1fr; }

  .copy-btn {
    grid-column: 2;
    justify-self: start;
  }

  .site-footer__base {
    flex-direction: column;
    align-items: flex-start;
    gap: .65rem;
  }
}

/* ---------- 16. 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}