/* =========================================================
   球盟会主站 / site.css
   深空蓝指挥台 · 框架式导航 · 精密网格
   ========================================================= */

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

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

body { margin: 0; }

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd, pre { margin: 0; }

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

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

a { color: inherit; text-decoration: none; }

button { font: inherit; color: inherit; background: none; border: 0; }

table { border-collapse: collapse; width: 100%; }

[hidden] { display: none !important; }

/* ---------- 2. Tokens ---------- */
:root {
  /* 色彩 */
  --ink-900: #061324;
  --ink-800: #0B1F38;
  --teal-900: #0E3B4A;
  --wine-900: #5A1F3D;
  --indigo-900: #26305E;
  --cyan: #35F0CF;
  --cyan-dim: #1FAF9A;
  --amber: #FFB347;
  --ice: #EAF6FF;
  --mist: #9CB3C7;
  --grid: #23445C;

  /* 字体 */
  --font-sans: "HarmonyOS Sans SC", "Noto Sans SC", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system,
    "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", "SFMono-Regular", ui-monospace,
    Menlo, Consolas, "Liberation Mono", monospace;

  /* 版式 */
  --max: 1440px;
  --gutter: clamp(16px, 4vw, 48px);
  --header-h: 64px;
  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  background: var(--ink-900);
  color: var(--ice);
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.04em;
}

p { margin-bottom: 1em; }
p:last-child { margin-bottom: 0; }

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 0;
}

[id] { scroll-margin-top: calc(var(--header-h) + 24px); }

/* ---------- 4. 工具类 ---------- */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.container {
  width: 100%;
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.site-main { display: block; }

.section { padding-block: clamp(48px, 7vw, 96px); }
.section--tight { padding-block: clamp(32px, 4vw, 56px); }

.band-deep { background: var(--ink-800); }
.band-teal { background: var(--teal-900); }
.band-wine { background: var(--wine-900); }
.band-indigo { background: var(--indigo-900); }

.hairline {
  border: 0;
  border-top: 1px solid var(--grid);
  margin: 0;
}

.text-amber { color: var(--amber); }
.text-cyan { color: var(--cyan); }
.text-mist { color: var(--mist); }

/* ---------- 5. 排版组件 ---------- */
.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 16px;
}
.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: currentColor;
  flex: none;
}

.display {
  font-size: clamp(40px, 9vw, 96px);
  line-height: 0.94;
  letter-spacing: 0.02em;
  font-weight: 700;
}
.h1 { font-size: clamp(32px, 5vw, 64px); line-height: 1.05; letter-spacing: 0.04em; }
.h2 { font-size: clamp(26px, 3.4vw, 40px); line-height: 1.15; letter-spacing: 0.04em; }
.h3 { font-size: clamp(20px, 2.2vw, 28px); line-height: 1.3; letter-spacing: 0.03em; }

.lede {
  font-size: clamp(16px, 1.3vw, 18px);
  color: var(--mist);
  max-width: 62ch;
}

.data-num {
  font-family: var(--font-mono);
  font-feature-settings: "tnum" 1;
  letter-spacing: 0;
  color: var(--amber);
}

.prose { max-width: 70ch; }
.prose p { margin-bottom: 1.1em; }
.prose ul, .prose ol { padding-left: 1.3em; margin-bottom: 1.1em; }
.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }
.prose li { margin-bottom: 0.4em; }
.prose a { color: var(--cyan); text-decoration: underline; text-underline-offset: 3px; }
.prose a:hover { color: var(--amber); }

/* ---------- 6. 状态点与标签 ---------- */
.status-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  flex: none;
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(53, 240, 207, 0.16);
  vertical-align: middle;
  margin-right: 8px;
}
.status-dot--amber { background: var(--amber); box-shadow: 0 0 0 3px rgba(255, 179, 71, 0.16); }
.status-dot--mist { background: var(--mist); box-shadow: 0 0 0 3px rgba(156, 179, 199, 0.14); }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  line-height: 1.5;
  border: 1px solid var(--grid);
  color: var(--mist);
  background: rgba(35, 68, 92, 0.18);
}
.tag--signal { border-color: rgba(53, 240, 207, 0.5); color: var(--cyan); }
.tag--amber { border-color: rgba(255, 179, 71, 0.5); color: var(--amber); }

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.08em;
  line-height: 1.4;
  border: 1px solid transparent;
  border-radius: 0;
  text-align: center;
  cursor: pointer;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease),
    border-color 0.18s var(--ease), box-shadow 0.18s var(--ease),
    transform 0.18s var(--ease);
}

.btn-signal {
  background: var(--cyan);
  border-color: var(--cyan);
  color: #03201c;
}
.btn-signal:hover,
.btn-signal:focus-visible {
  background: #7ffbe6;
  border-color: #7ffbe6;
  box-shadow: 0 0 0 3px rgba(53, 240, 207, 0.2);
}

.btn-outline {
  background: transparent;
  border-color: var(--grid);
  color: var(--ice);
}
.btn-outline:hover,
.btn-outline:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
}

.btn-amber {
  background: var(--amber);
  border-color: var(--amber);
  color: #2a1600;
}
.btn-amber:hover,
.btn-amber:focus-visible {
  background: #ffc978;
  border-color: #ffc978;
  box-shadow: 0 0 0 3px rgba(255, 179, 71, 0.22);
}

.btn-ghost {
  background: transparent;
  border-color: transparent;
  color: var(--cyan);
  padding-inline: 0;
}
.btn-ghost:hover,
.btn-ghost:focus-visible { color: var(--amber); }

/* ---------- 8. Skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 300;
  padding: 10px 16px;
  background: var(--cyan);
  color: #03201c;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.08em;
  transform: translateY(-200%);
  transition: transform 0.18s var(--ease);
}
.skip-link:focus,
.skip-link:focus-visible {
  transform: translateY(0);
  outline: 2px solid var(--ice);
  outline-offset: 2px;
}

/* ---------- 9. Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 120;
  background: rgba(6, 19, 36, 0.94);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--grid);
  color: var(--ice);
  transition: border-color 0.22s var(--ease), box-shadow 0.22s var(--ease);
}
.site-header[data-scrolled] {
  border-bottom-color: rgba(53, 240, 207, 0.38);
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.45);
}

.progress-rail {
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: rgba(35, 68, 92, 0.7);
  pointer-events: none;
  z-index: 3;
}
.progress-bar {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--cyan-dim), var(--cyan) 62%, var(--amber));
  transition: width 0.12s linear;
}

.header-frame {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  max-width: 1560px;
  margin-inline: auto;
  padding-inline: var(--gutter);
  min-height: var(--header-h);
}

/* 品牌 */
.brand {
  order: 1;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: none;
  padding: 6px 0;
}

.brand-glyph {
  position: relative;
  display: block;
  width: 22px;
  height: 22px;
  flex: none;
  border: 1px solid var(--cyan);
  background: rgba(53, 240, 207, 0.06);
}
.brand-glyph::before {
  content: "";
  position: absolute;
  inset: 5px;
  background: var(--amber);
}
.brand-glyph::after {
  content: "";
  position: absolute;
  top: -1px;
  right: -1px;
  width: 6px;
  height: 6px;
  background: var(--ink-900);
  border-left: 1px solid var(--cyan);
  border-bottom: 1px solid var(--cyan);
}

.brand-name {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--ice);
  white-space: nowrap;
}

.brand-suffix {
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--mist);
  padding-left: 8px;
  border-left: 1px solid var(--grid);
  white-space: nowrap;
}

.brand-meta {
  display: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--cyan);
  padding: 2px 6px;
  border: 1px solid rgba(53, 240, 207, 0.4);
  white-space: nowrap;
}

/* 移动菜单按钮 */
.nav-toggle {
  order: 3;
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: stretch;
  gap: 5px;
  width: 44px;
  height: 40px;
  padding: 0 10px;
  margin-left: 10px;
  border: 1px solid var(--grid);
  background: rgba(11, 31, 56, 0.8);
  cursor: pointer;
  transition: border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}
.nav-toggle:hover { border-color: var(--cyan); }
.nav-toggle-line {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--ice);
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease),
    background-color 0.2s var(--ease);
}
.site-header[data-open] .nav-toggle { border-color: var(--cyan); }
.site-header[data-open] .nav-toggle-line { background: var(--cyan); }
.site-header[data-open] .nav-toggle-line:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.site-header[data-open] .nav-toggle-line:nth-child(2) { transform: translateY(-7px) rotate(-45deg); }

/* 导航 */
.site-nav {
  order: 4;
  display: none;
  width: 100%;
}

.site-header[data-open] .site-nav {
  display: block;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--ink-800);
  border-top: 1px solid var(--grid);
  border-bottom: 1px solid var(--grid);
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.55);
  max-height: calc(100vh - var(--header-h));
  overflow-y: auto;
}

.nav-list {
  display: flex;
  flex-direction: column;
}

.nav-item { display: flex; }

.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 14px var(--gutter);
  font-size: 15px;
  letter-spacing: 0.1em;
  color: var(--mist);
  border-top: 1px solid rgba(35, 68, 92, 0.7);
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}
.nav-list li:first-child .nav-link { border-top: 0; }

.nav-link::before {
  content: attr(data-num);
  display: none;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--cyan-dim);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: var(--gutter);
  right: var(--gutter);
  bottom: 6px;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.2s var(--ease);
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--ice);
  background: rgba(53, 240, 207, 0.07);
}
.nav-link:hover::after,
.nav-link:focus-visible::after { transform: scaleX(1); }

.nav-link[aria-current="page"] {
  color: var(--ice);
  background: rgba(53, 240, 207, 0.1);
  box-shadow: inset 2px 0 0 var(--cyan);
}
.nav-link[aria-current="page"]::after { transform: scaleX(1); }
.nav-link[aria-current="page"]::before { color: var(--amber); }

/* 头部行动区 */
.header-actions {
  order: 2;
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
}
.header-actions .btn {
  padding: 8px 12px;
  font-size: 13px;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

/* ---------- 10. 面包屑 ---------- */
.breadcrumb {
  padding-block: 16px;
  border-bottom: 1px solid var(--grid);
  background: rgba(11, 31, 56, 0.5);
}
.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
}
.breadcrumb-item { display: inline-flex; align-items: center; }
.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  color: var(--grid);
  margin: 0 8px;
}
.breadcrumb-link { color: var(--mist); transition: color 0.18s var(--ease); }
.breadcrumb-link:hover,
.breadcrumb-link:focus-visible { color: var(--cyan); }
.breadcrumb-item [aria-current="page"] { color: var(--ice); }

/* ---------- 11. 网格系统 ---------- */
.grid { display: grid; gap: clamp(16px, 2vw, 28px); }
.grid-2 { grid-template-columns: 1fr; }
.grid-3 { grid-template-columns: 1fr; }

.split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
}

/* ---------- 12. 面板 ---------- */
.panel {
  position: relative;
  background: var(--ink-800);
  border: 1px solid var(--grid);
  padding: clamp(20px, 2.4vw, 28px);
}
.panel::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 14px;
  height: 14px;
  border-top: 2px solid var(--cyan);
  border-left: 2px solid var(--cyan);
  pointer-events: none;
}
.panel--plain { background: transparent; }
.panel--amber::before { border-top-color: var(--amber); border-left-color: var(--amber); }

.panel-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 12px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--grid);
}
.panel-title {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--ice);
}
.panel-meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mist);
  white-space: nowrap;
}

/* ---------- 13. 媒体容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--grid);
  background: linear-gradient(160deg, var(--teal-900) 0%, var(--ink-800) 58%, #071a2e 100%);
}
.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.55;
  background-image:
    linear-gradient(to right, rgba(35, 68, 92, 0.55) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(35, 68, 92, 0.55) 1px, transparent 1px);
  background-size: 32px 32px;
}
.media-frame > img,
.media-frame > svg,
.media-frame > picture,
.media-frame > picture > img {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--wine { background: linear-gradient(150deg, var(--wine-900), var(--ink-800) 70%); }
.media-frame--indigo { background: linear-gradient(150deg, var(--indigo-900), var(--ink-800) 70%); }

.media-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ---------- 14. 数据表 ---------- */
.data-table { font-size: 14px; }
.data-table th {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-align: left;
  color: var(--amber);
  padding: 10px 12px;
  border-bottom: 1px solid var(--grid);
  background: rgba(35, 68, 92, 0.22);
  white-space: nowrap;
}
.data-table td {
  padding: 12px;
  border-bottom: 1px solid rgba(35, 68, 92, 0.6);
  color: var(--ice);
  vertical-align: top;
}
.data-table tbody tr { transition: background-color 0.18s var(--ease); }
.data-table tbody tr:hover { background: rgba(53, 240, 207, 0.06); }
.data-table .num {
  font-family: var(--font-mono);
  text-align: right;
  color: var(--amber);
  white-space: nowrap;
}

/* ---------- 15. 章节目录 ---------- */
.toc {
  position: sticky;
  top: calc(var(--header-h) + 20px);
  border-left: 1px solid var(--grid);
  padding-left: 4px;
}
.toc-title {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 12px;
  padding-left: 12px;
}
.toc-list { display: flex; flex-direction: column; }
.toc-link {
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  line-height: 1.5;
  color: var(--mist);
  border-left: 2px solid transparent;
  margin-left: -5px;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease),
    background-color 0.18s var(--ease);
}
.toc-link:hover,
.toc-link:focus-visible { color: var(--ice); border-left-color: var(--cyan-dim); }
.toc-link[aria-current="true"] {
  color: var(--cyan);
  border-left-color: var(--cyan);
  background: rgba(53, 240, 207, 0.07);
}

/* ---------- 16. Footer ---------- */
.site-footer {
  position: relative;
  background: var(--ink-800);
  color: var(--mist);
  border-top: 1px solid var(--grid);
}
.site-footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan) 25%, var(--amber) 78%, transparent);
  opacity: 0.6;
  pointer-events: none;
}

.footer-frame {
  width: 100%;
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: var(--gutter);
  padding-top: clamp(36px, 5vw, 64px);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3vw, 36px);
  padding-bottom: clamp(28px, 4vw, 48px);
}

.footer-col { min-width: 0; }

.footer-brand { display: flex; flex-direction: column; gap: 14px; }

.footer-logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ice);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.1em;
}
.footer-logo:hover .footer-logo-text,
.footer-logo:focus-visible .footer-logo-text { color: var(--cyan); }
.footer-logo-text { transition: color 0.18s var(--ease); }
.footer-logo-suffix {
  margin-left: 8px;
  padding-left: 8px;
  border-left: 1px solid var(--grid);
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.16em;
  color: var(--mist);
}

.footer-tagline {
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
  max-width: 32ch;
  margin: 0;
}

.footer-status {
  display: flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  margin: 0;
}

.footer-heading {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
  margin: 0 0 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--grid);
}

.footer-list { display: flex; flex-direction: column; }

.footer-link {
  display: inline-block;
  padding: 5px 0;
  font-size: 14px;
  color: var(--mist);
  transition: color 0.18s var(--ease), transform 0.18s var(--ease);
}
.footer-link:hover,
.footer-link:focus-visible {
  color: var(--cyan);
  transform: translateX(3px);
}

.footer-contact { display: flex; flex-direction: column; gap: 12px; }

.footer-item { display: flex; flex-direction: column; gap: 2px; }

.footer-item-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan-dim);
}

.footer-item-value {
  font-size: 14px;
  line-height: 1.6;
  color: var(--ice);
  overflow-wrap: anywhere;
  word-break: break-word;
}
.footer-item-value--mono {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--amber);
}

.footer-note {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid rgba(35, 68, 92, 0.7);
  font-size: 12px;
  line-height: 1.7;
  color: var(--mist);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding-block: 20px;
  border-top: 1px solid var(--grid);
}

.footer-copy,
.footer-icp {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--mist);
  margin: 0;
}
.footer-icp { color: var(--cyan-dim); }

/* ---------- 17. 平板 ---------- */
@media (min-width: 768px) {
  .grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: 1 / -1; }
}

/* ---------- 18. 桌面 ---------- */
@media (min-width: 1100px) {
  :root { --header-h: 72px; }

  .header-frame { gap: 24px; }

  .nav-toggle { display: none; }

  .site-nav {
    display: block;
    order: 2;
    width: auto;
    margin-left: auto;
  }
  .site-nav,
  .site-header[data-open] .site-nav {
    position: static;
    background: transparent;
    border: 0;
    box-shadow: none;
    max-height: none;
    overflow: visible;
  }

  .nav-list { flex-direction: row; align-items: center; gap: 2px; }
  .nav-item { display: block; }

  .nav-link {
    padding: 10px 14px;
    font-size: 14px;
    border-top: 0;
    width: auto;
    box-shadow: none;
  }
  .nav-list li:first-child .nav-link { border-top: 0; }

  .nav-link::before { display: inline-block; }

  .nav-link::after {
    left: 14px;
    right: 14px;
    bottom: 4px;
  }

  .nav-link[aria-current="page"] {
    box-shadow: none;
    background: rgba(53, 240, 207, 0.1);
  }

  .header-actions {
    order: 3;
    margin-left: 0;
  }
  .header-actions .btn {
    padding: 10px 18px;
    font-size: 14px;
  }

  .split { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }
  .split--reverse { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }

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

  .footer-grid {
    grid-template-columns: 1.5fr 0.9fr 0.9fr 1.3fr;
    gap: 0;
  }
  .footer-brand { grid-column: auto; padding-right: clamp(20px, 2.5vw, 36px); }
  .footer-col:not(.footer-brand) {
    padding-left: clamp(20px, 2.5vw, 36px);
    border-left: 1px solid var(--grid);
  }
}

/* ---------- 19. 大屏 ---------- */
@media (min-width: 1400px) {
  .brand-meta { display: inline-block; }
}

/* ---------- 20. 小屏微调 ---------- */
@media (max-width: 400px) {
  .brand-suffix { display: none; }
  .brand-name { font-size: 16px; letter-spacing: 0.08em; }
  .header-actions .btn { padding: 8px 10px; font-size: 12px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}

/* ---------- 21. 减少动效 ---------- */
@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;
  }
  .nav-link:hover,
  .nav-link:focus-visible,
  .footer-link:hover,
  .footer-link:focus-visible { transform: none; }
  .progress-bar { transition: none; }
}

/* ---------- 22. 打印 ---------- */
@media print {
  .site-header,
  .site-footer,
  .skip-link,
  .toc { display: none !important; }
  body { background: #fff; color: #111; }
  a { color: #111; text-decoration: underline; }
}