/* ==========================================================================
   万搏品牌站 · 共享样式表 /assets/site.css
   高原导航体系：深蓝基调 + 晨雾白留白 + 经幡橙 / 青稞绿状态色
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 150px;
}

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

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

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

button { font: inherit; color: inherit; }

a { color: inherit; }

/* ---------- 2. 变量 ---------- */
:root {
  --c-lake: #0B3D5C;
  --c-mist: #F4F7F9;
  --c-orange: #E8752B;
  --c-barley: #3E7C4A;
  --c-deep: #07293E;
  --c-lake-mid: #1E6E8C;
  --c-line: #C9D6DE;
  --c-gravel: #6B7A85;
  --c-orange-soft: #FFD9B8;
  --c-green-soft: #DFF0E4;
  --c-white: #FFFFFF;

  --font-display: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC",
    "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC",
    "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-num: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, "Courier New", monospace;

  --wrap: 1180px;
  --gutter: clamp(16px, 3.6vw, 40px);
  --radius: 2px;
  --hairline: 1px solid var(--c-line);
  --shadow-soft: 0 1px 0 rgba(11, 61, 92, .04), 0 16px 34px -28px rgba(7, 41, 62, .70);
  --shadow-lift: 0 24px 44px -32px rgba(7, 41, 62, .78);
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- 3. 中文排版基底 ---------- */
body {
  min-height: 100vh;
  background-color: var(--c-mist);
  color: var(--c-lake);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.85;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
}

/* 等高线 + 经纬网格底纹（纯 CSS，不占用内容层） */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(0deg, transparent 0 47px, rgba(201, 214, 222, .42) 47px 48px),
    repeating-linear-gradient(90deg, transparent 0 47px, rgba(201, 214, 222, .42) 47px 48px),
    repeating-radial-gradient(circle at 88% 116%, transparent 0 34px, rgba(30, 110, 140, .10) 34px 35px);
  background-size: 48px 48px, 48px 48px, 940px 640px;
  background-position: 0 0, 0 0, 100% 100%;
  background-repeat: repeat, repeat, no-repeat;
}

main { position: relative; z-index: 1; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: .08em;
  color: var(--c-lake);
}

/* ---------- 4. 跳转链接 ---------- */
.skip-link {
  position: absolute;
  left: var(--gutter);
  top: -72px;
  z-index: 140;
  display: inline-block;
  padding: 10px 18px;
  background: var(--c-orange);
  color: #fff;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .08em;
  text-decoration: none;
  border-radius: var(--radius);
  transition: top .2s var(--ease);
}
.skip-link:focus { top: 10px; }

/* ---------- 5. 头部 · 刊头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--c-lake);
  color: var(--c-mist);
  border-bottom: 2px solid var(--c-orange);
}

.masthead {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  align-items: center;
  gap: 10px 20px;
  width: min(var(--wrap), 100%);
  margin-inline: auto;
  padding: 13px var(--gutter) 12px;
}

.masthead__region {
  font-size: 11px;
  line-height: 1.5;
  letter-spacing: .14em;
  color: rgba(244, 247, 249, .66);
}

.masthead__brand {
  justify-self: center;
  margin-right: -.2em;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(20px, 2.5vw, 28px);
  letter-spacing: .2em;
  color: var(--c-mist);
  text-decoration: none;
  white-space: nowrap;
  transition: color .2s var(--ease);
}
.masthead__brand:hover { color: var(--c-orange-soft); }

.masthead__meta {
  justify-self: end;
  display: flex;
  align-items: center;
  gap: 14px;
}

.masthead__section {
  padding-left: 10px;
  border-left: 2px solid var(--c-orange);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--c-orange-soft);
  white-space: nowrap;
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 7px 13px;
  background: transparent;
  color: var(--c-mist);
  border: 1px solid rgba(244, 247, 249, .34);
  border-radius: var(--radius);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .14em;
  cursor: pointer;
  transition: border-color .2s var(--ease), color .2s var(--ease), background .2s var(--ease);
}
.nav-toggle:hover { border-color: var(--c-orange); color: var(--c-orange-soft); }
.nav-toggle[aria-expanded="true"] {
  background: rgba(244, 247, 249, .08);
  border-color: var(--c-orange);
  color: var(--c-orange-soft);
}

.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 3px;
  width: 14px;
}
.nav-toggle__bars span {
  display: block;
  height: 2px;
  background: currentColor;
  transition: transform .22s var(--ease), opacity .22s var(--ease);
}
.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); }

/* ---------- 6. 头部 · 三段快捷带 ---------- */
.quick-bar {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  background: var(--c-deep);
  border-top: 1px solid rgba(244, 247, 249, .14);
}
.quick-bar__item + .quick-bar__item { border-left: 1px solid rgba(244, 247, 249, .14); }

.quick-bar__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px clamp(12px, 2.6vw, 28px);
  color: var(--c-mist);
  text-decoration: none;
  transition: background .2s var(--ease), color .2s var(--ease);
}
.quick-bar__link:hover,
.quick-bar__link:focus-visible { background: var(--c-lake-mid); color: #fff; }

.quick-bar__label {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .12em;
}
.quick-bar__hint {
  font-size: 11.5px;
  letter-spacing: .04em;
  color: rgba(244, 247, 249, .60);
}
.quick-bar__link:hover .quick-bar__hint { color: var(--c-orange-soft); }

/* ---------- 7. 头部 · 九宫格面板 ---------- */
.mega-nav {
  position: relative;
  background: var(--c-mist);
  color: var(--c-lake);
  border-top: 1px solid var(--c-line);
}

.mega-nav__inner {
  width: min(var(--wrap), 100%);
  margin-inline: auto;
  padding: clamp(16px, 2.6vw, 26px) var(--gutter) clamp(20px, 3vw, 30px);
}

.mega-nav__grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  grid-template-rows: repeat(3, auto);
  grid-auto-flow: column;
  border-top: 1px solid var(--c-line);
  border-left: 1px solid var(--c-line);
}

.mega-nav__cell {
  background: var(--c-white);
  border-right: 1px solid var(--c-line);
  border-bottom: 1px solid var(--c-line);
}

.mega-nav__link {
  position: relative;
  display: block;
  height: 100%;
  padding: 14px 16px 16px;
  color: var(--c-lake);
  text-decoration: none;
  transition: background .2s var(--ease), color .2s var(--ease);
}
.mega-nav__link:hover { background: #EDF3F7; }

.mega-nav__link[aria-current="page"] {
  background: rgba(255, 217, 184, .32);
}
.mega-nav__link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  bottom: 12px;
  width: 3px;
  background: var(--c-orange);
}
.mega-nav__link[aria-current="page"] .mega-nav__name { color: var(--c-orange); }

.mega-nav__index {
  display: block;
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--c-gravel);
}
.mega-nav__name {
  display: block;
  margin-top: 3px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: .1em;
  color: var(--c-lake);
}
.mega-nav__desc {
  display: block;
  margin-top: 3px;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--c-gravel);
}

.mega-nav__cell--info {
  padding: 14px 16px 16px;
  background: var(--c-lake);
  color: var(--c-mist);
}
.mega-nav__info-title {
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: .18em;
  color: rgba(244, 247, 249, .62);
}
.mega-nav__info-text {
  margin-top: 6px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: .1em;
  color: var(--c-mist);
}
.mega-nav__info-meta {
  margin-top: 4px;
  font-size: 12.5px;
  letter-spacing: .04em;
  color: var(--c-orange-soft);
}

/* 脚本可用时才折叠为浮层 */
.is-js .mega-nav {
  position: absolute;
  left: 0;
  right: 0;
  top: 100%;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  visibility: hidden;
  border-bottom: 3px solid var(--c-lake);
  box-shadow: 0 26px 44px -34px rgba(7, 41, 62, .85);
  transition: max-height .3s var(--ease), opacity .2s var(--ease), visibility 0s linear .3s;
}
.is-js .mega-nav[data-open] {
  max-height: min(78vh, 720px);
  overflow-y: auto;
  opacity: 1;
  visibility: visible;
  transition: max-height .34s var(--ease), opacity .2s var(--ease), visibility 0s;
}

/* ---------- 8. 页脚 ---------- */
.site-footer {
  position: relative;
  z-index: 1;
  margin-top: clamp(48px, 7vw, 96px);
  background: var(--c-deep);
  color: var(--c-mist);
}

.footer-ridge {
  height: 12px;
  background-color: var(--c-lake);
  background-image:
    repeating-linear-gradient(90deg, var(--c-orange) 0 3px, transparent 3px 14px),
    repeating-radial-gradient(circle at 50% -520%, transparent 0 40px, rgba(244, 247, 249, .16) 40px 41px);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: minmax(200px, 1.15fr) repeat(3, minmax(0, 1fr));
  gap: clamp(22px, 3vw, 42px);
  width: min(var(--wrap), 100%);
  margin-inline: auto;
  padding: clamp(30px, 4.6vw, 54px) var(--gutter) clamp(20px, 3vw, 30px);
}

.footer-lede__brand {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 22px;
  letter-spacing: .18em;
  color: var(--c-mist);
}
.footer-lede__text {
  max-width: 32ch;
  margin-top: 10px;
  font-size: 13.5px;
  line-height: 1.8;
  color: rgba(244, 247, 249, .66);
}

.footer-col__title {
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid rgba(244, 247, 249, .18);
  font-family: var(--font-num);
  font-size: 11.5px;
  letter-spacing: .2em;
  color: var(--c-orange-soft);
}

.footer-col__list { display: grid; gap: 8px; }

.footer-col__link {
  display: inline-block;
  font-size: 14px;
  color: rgba(244, 247, 249, .86);
  text-decoration: none;
  transition: color .2s var(--ease), transform .2s var(--ease);
}
.footer-col__link:hover,
.footer-col__link:focus-visible { color: var(--c-orange); transform: translateX(3px); }

.footer-contact__item {
  font-size: 13.5px;
  line-height: 1.8;
  color: rgba(244, 247, 249, .82);
  word-break: break-word;
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 6px 26px;
  width: min(var(--wrap), 100%);
  margin-inline: auto;
  padding: 14px var(--gutter) 24px;
  border-top: 1px solid rgba(244, 247, 249, .16);
  font-size: 12.5px;
  color: rgba(244, 247, 249, .62);
}
.footer-base__region { letter-spacing: .08em; color: var(--c-orange-soft); }
.footer-base__note { font-family: var(--font-num); letter-spacing: .04em; }

/* ---------- 9. 通用容器 ---------- */
.wrap {
  width: min(var(--wrap), 100%);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.prose {
  max-width: 68ch;
  font-size: 16.5px;
  line-height: 1.9;
  color: var(--c-lake);
}
.prose p { margin-bottom: 1.2em; }
.prose h2 { margin: 1.6em 0 .6em; font-size: clamp(22px, 2.6vw, 28px); letter-spacing: .08em; }
.prose h3 { margin: 1.4em 0 .5em; font-size: 19px; letter-spacing: .07em; }
.prose ul, .prose ol { margin: 0 0 1.2em 1.3em; list-style: disc; }
.prose ol { list-style: decimal; }
.prose li { margin-bottom: .5em; }
.prose a { color: var(--c-lake-mid); text-decoration: underline; text-underline-offset: 3px; }
.prose a:hover { color: var(--c-orange); }
.prose strong { font-weight: 800; }

.num {
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  letter-spacing: .04em;
}

/* ---------- 10. 章节头与色带 ---------- */
.section { padding: clamp(34px, 5.6vw, 72px) 0; }

.section__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: 2px 16px;
  margin-bottom: clamp(18px, 2.6vw, 30px);
}
.section__num {
  padding-top: 6px;
  font-family: var(--font-num);
  font-size: 12.5px;
  letter-spacing: .2em;
  color: var(--c-orange);
}
.section__title {
  font-size: clamp(25px, 3.3vw, 33px);
  letter-spacing: .09em;
}
.section__lede {
  grid-column: 2;
  margin-top: 8px;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-gravel);
}

.rule-band {
  height: 3px;
  border: 0;
  background: var(--c-line);
}
.rule-band--orange { background: linear-gradient(90deg, var(--c-orange) 0 22%, var(--c-line) 22% 100%); }
.rule-band--green { background: linear-gradient(90deg, var(--c-barley) 0 16%, var(--c-line) 16% 100%); }
.rule-band--lake { background: linear-gradient(90deg, var(--c-lake) 0 40%, var(--c-line) 40% 100%); }

/* ---------- 11. 网格 ---------- */
.grid { display: grid; gap: clamp(14px, 1.8vw, 22px); }
.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)); }

/* ---------- 12. 专题研究板卡片 ---------- */
.panel {
  position: relative;
  overflow: hidden;
  padding: clamp(16px, 2vw, 24px);
  background: var(--c-white);
  border: var(--hairline);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
  transition: transform .24s var(--ease), box-shadow .24s var(--ease), border-color .24s var(--ease);
}
.panel::after {
  content: "";
  position: absolute;
  right: -70px;
  bottom: -70px;
  width: 170px;
  height: 170px;
  border-radius: 50%;
  background-image: repeating-radial-gradient(circle at 50% 50%, transparent 0 11px, rgba(30, 110, 140, .18) 11px 12px);
  opacity: 0;
  transform: scale(.72);
  pointer-events: none;
  transition: opacity .3s var(--ease), transform .34s var(--ease);
}
.panel:hover {
  transform: translateY(-4px);
  border-color: var(--c-lake-mid);
  box-shadow: var(--shadow-lift);
}
.panel:hover::after { opacity: 1; transform: scale(1); }

.panel__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}
.panel__title { font-size: clamp(17px, 1.6vw, 20px); letter-spacing: .07em; }
.panel__body { font-size: 15px; line-height: 1.85; color: var(--c-lake); }
.panel__body p + p { margin-top: .8em; }
.panel__foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--c-line);
  font-size: 13px;
  color: var(--c-gravel);
}

/* ---------- 13. 标签与状态点 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-white);
  color: var(--c-gravel);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: .12em;
  white-space: nowrap;
}
.tag--orange { background: var(--c-orange-soft); border-color: #F0B17C; color: var(--c-lake); }
.tag--green { background: var(--c-green-soft); border-color: #A6CDB3; color: var(--c-lake); }
.tag--blue { background: rgba(30, 110, 140, .10); border-color: rgba(30, 110, 140, .34); color: var(--c-lake-mid); }

.status-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-right: 7px;
  border-radius: 50%;
  background: var(--c-barley);
  vertical-align: middle;
}
.status-dot--pending { background: var(--c-orange); }
.status-dot--idle { background: var(--c-gravel); }

/* ---------- 14. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border: 1px solid var(--c-lake);
  border-radius: var(--radius);
  background: var(--c-lake);
  color: var(--c-mist);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .08em;
  text-decoration: none;
  cursor: pointer;
  transition: background .2s var(--ease), color .2s var(--ease), border-color .2s var(--ease), transform .2s var(--ease);
}
.btn:hover { transform: translateY(-1px); background: var(--c-lake-mid); border-color: var(--c-lake-mid); }

.btn--accent { background: var(--c-orange); border-color: var(--c-orange); color: #fff; }
.btn--accent:hover { background: #CF6520; border-color: #CF6520; }

.btn--ghost { background: transparent; color: var(--c-lake); border-color: var(--c-line); }
.btn--ghost:hover { background: var(--c-white); border-color: var(--c-lake-mid); color: var(--c-lake-mid); }

.btn--quiet {
  padding-inline: 2px;
  background: transparent;
  border-color: transparent;
  color: var(--c-lake-mid);
}
.btn--quiet:hover { background: transparent; color: var(--c-orange); }

/* ---------- 15. 面包屑 ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--c-gravel);
}
.crumbs__item { display: inline-flex; align-items: center; gap: 8px; }
.crumbs a { color: var(--c-lake-mid); text-decoration: none; }
.crumbs a:hover { color: var(--c-orange); text-decoration: underline; text-underline-offset: 3px; }
.crumbs__sep { color: var(--c-line); }
.crumbs [aria-current="page"] { color: var(--c-lake); font-weight: 700; }

/* ---------- 16. 键值对照表 ---------- */
.data-list { border-top: 1px solid var(--c-line); }
.data-list__row {
  display: grid;
  grid-template-columns: minmax(96px, 32%) minmax(0, 1fr);
  gap: 14px;
  padding: 11px 0;
  border-bottom: 1px solid var(--c-line);
}
.data-list__key { font-size: 12.5px; letter-spacing: .12em; color: var(--c-gravel); }
.data-list__value { font-size: 15px; line-height: 1.8; color: var(--c-lake); }

/* ---------- 17. 折叠问答组 ---------- */
.fold {
  background: var(--c-white);
  border: var(--hairline);
  border-radius: var(--radius);
  transition: border-color .2s var(--ease);
}
.fold + .fold { margin-top: 10px; }
.fold[data-open] { border-color: var(--c-lake-mid); }

.fold__btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 14px 18px;
  border: 0;
  background: transparent;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: .07em;
  text-align: left;
  color: var(--c-lake);
  cursor: pointer;
  transition: color .2s var(--ease);
}
.fold__btn:hover { color: var(--c-lake-mid); }
.fold__btn::after {
  content: "+";
  flex: none;
  font-family: var(--font-num);
  font-size: 18px;
  color: var(--c-orange);
  transition: transform .2s var(--ease);
}
.fold__btn[aria-expanded="true"]::after { content: "\2013"; }

.fold__panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height .24s var(--ease);
}
.fold__panel[data-open] { max-height: 1000px; }

.fold__body {
  margin: 0 18px 18px;
  padding-top: 14px;
  border-top: 1px solid var(--c-line);
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-lake);
}

/* ---------- 18. 图片容器（供页面阶段放置占位） ---------- */
.media { display: block; }
.media__frame {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border: var(--hairline);
  border-radius: var(--radius);
  background-color: var(--c-mist);
  background-image:
    repeating-radial-gradient(circle at 82% 108%, transparent 0 26px, rgba(30, 110, 140, .14) 26px 27px),
    linear-gradient(155deg, rgba(30, 110, 140, .10), rgba(201, 214, 222, .34));
}
.media__frame > img,
.media__frame > svg {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media__caption {
  margin-top: 9px;
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: .04em;
  color: var(--c-gravel);
}
.media--wide .media__frame { aspect-ratio: 21 / 9; }
.media--square .media__frame { aspect-ratio: 1 / 1; }
.media--tall .media__frame { aspect-ratio: 4 / 5; }

/* ---------- 19. 动效元素 ---------- */
.is-js .reveal,
.is-js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .55s var(--ease), transform .55s var(--ease);
}
.is-js .reveal.is-visible,
.is-js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 120;
  width: 100%;
  height: 3px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--c-orange), var(--c-barley));
  pointer-events: none;
}

.to-top {
  position: fixed;
  right: clamp(14px, 2.6vw, 28px);
  bottom: clamp(14px, 2.6vw, 28px);
  z-index: 90;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--c-line);
  border-radius: 50%;
  background: var(--c-white);
  color: var(--c-lake);
  font-family: var(--font-num);
  font-size: 16px;
  cursor: pointer;
  box-shadow: var(--shadow-soft);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .24s var(--ease), transform .24s var(--ease),
    visibility 0s linear .24s, border-color .2s var(--ease), color .2s var(--ease);
}
.to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition: opacity .24s var(--ease), transform .24s var(--ease),
    visibility 0s, border-color .2s var(--ease), color .2s var(--ease);
}
.to-top:hover { border-color: var(--c-orange); color: var(--c-orange); }

[data-copy] {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-white);
  color: var(--c-lake);
  font-size: 13px;
  cursor: pointer;
  transition: border-color .2s var(--ease), color .2s var(--ease);
}
[data-copy]:hover { border-color: var(--c-lake-mid); color: var(--c-lake-mid); }
[data-copy][data-copied] { border-color: var(--c-barley); color: var(--c-barley); }
[data-copy][data-copied]::after {
  content: "已复制";
  font-size: 11.5px;
  letter-spacing: .1em;
}

/* ---------- 20. 焦点与无障碍 ---------- */
:focus-visible {
  outline: 2px solid var(--c-orange);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  .is-js .reveal,
  .is-js [data-reveal] { opacity: 1 !important; transform: none !important; }
  .panel:hover { transform: none; }
  .footer-col__link:hover { transform: none; }
}

/* ---------- 21. 响应式 ---------- */
@media (max-width: 1080px) {
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .site-footer__inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-lede { grid-column: 1 / -1; }
}

@media (max-width: 820px) {
  html { scroll-padding-top: 130px; }

  .masthead {
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-areas:
      "brand meta"
      "region region";
    row-gap: 6px;
    padding: 10px var(--gutter);
  }
  .masthead__brand { grid-area: brand; justify-self: start; letter-spacing: .16em; margin-right: -.16em; }
  .masthead__meta { grid-area: meta; }
  .masthead__region { grid-area: region; font-size: 10.5px; letter-spacing: .1em; }
  .masthead__section { display: none; }

  .quick-bar__hint { display: none; }
  .quick-bar__link { justify-content: center; padding: 9px 10px; }
  .quick-bar__label { font-size: 12.5px; letter-spacing: .08em; }

  .mega-nav__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    grid-template-rows: none;
    grid-auto-flow: row;
  }
}

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

  .section__head { grid-template-columns: 1fr; }
  .section__num { padding-top: 0; }
  .section__lede { grid-column: 1; }

  .mega-nav__grid { grid-template-columns: 1fr; }
  .mega-nav__link { padding: 12px 14px 14px; }

  .site-footer__inner { grid-template-columns: 1fr; gap: 26px; }
  .footer-lede { grid-column: auto; }

  .data-list__row { grid-template-columns: 1fr; gap: 4px; }

  .footer-base { flex-direction: column; }
}

@media (max-width: 480px) {
  .quick-bar { grid-template-columns: 1fr; }
  .quick-bar__item + .quick-bar__item {
    border-left: 0;
    border-top: 1px solid rgba(244, 247, 249, .14);
  }
  .quick-bar__hint { display: inline; }
  .quick-bar__link { justify-content: flex-start; padding: 8px 16px; }

  .masthead__brand { font-size: 19px; }
}