/* ==========================================================================
   必搏 · 共享站点样式  /assets/site.css
   深靛蓝幕布 + 电光青结构线 + 暖琥珀节点 / 框架式导航 / 编辑部刊物节奏
   ========================================================================== */

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

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

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, blockquote, dl, dd, fieldset {
  margin: 0;
}

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

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

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

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

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

/* ---------- 2. 变量 ---------- */
:root {
  /* 色彩 */
  --indigo: #0E1836;
  --ink: #070E20;
  --cyan: #2BE3D2;
  --amber: #FFB352;
  --glass: rgba(255, 255, 255, 0.10);
  --glass-strong: rgba(255, 255, 255, 0.16);
  --text: #F2F6FF;
  --muted: #9AA9C9;
  --muted-soft: #C3D0EE;
  --line: #24345E;
  --paper: #F3F6FD;
  --paper-ink: #0E1836;
  --paper-body: #43526F;
  --green: #63E6A4;
  --coral: #FF7A6B;

  /* 字体 */
  --font-display: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", Georgia, "Times New Roman", serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", "Courier New", monospace;

  /* 版式与节奏 */
  --shell: 1360px;
  --gutter: clamp(18px, 3.2vw, 44px);
  --r-sm: 4px;
  --r-md: 10px;
  --r-lg: 18px;

  /* 动效 */
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --t: 150ms;
}

/* ---------- 3. 基础与中文排版 ---------- */
body {
  min-height: 100vh;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  color: var(--text);
  background-color: var(--indigo);
  background-image:
    radial-gradient(1100px 620px at 88% -12%, rgba(43, 227, 210, 0.10), transparent 62%),
    radial-gradient(880px 520px at -12% 22%, rgba(255, 179, 82, 0.07), transparent 66%);
  background-repeat: no-repeat;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: -0.02em;
  color: var(--text);
}

h1 { font-size: clamp(38px, 5.4vw, 76px); line-height: 1.04; letter-spacing: -0.03em; }
h2 { font-size: clamp(26px, 3.2vw, 42px); }
h3 { font-size: clamp(20px, 2.1vw, 27px); }
h4 { font-size: clamp(17px, 1.5vw, 20px); letter-spacing: -0.01em; }

p { overflow-wrap: break-word; }

strong, b { font-weight: 700; }

::selection { background: rgba(43, 227, 210, 0.32); color: #FFFFFF; }

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

#main-content { display: block; scroll-margin-top: 130px; }

/* ---------- 4. 通用工具类 ---------- */
.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.06em;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 500;
  font-size: 13px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--cyan);
}

.lede {
  max-width: 62ch;
  font-size: clamp(16px, 1.25vw, 18px);
  line-height: 1.8;
  color: var(--muted-soft);
}

.prose {
  max-width: 68ch;
  font-size: 16px;
  line-height: 1.85;
  color: #D6DEFF;
}

.prose > * + * { margin-top: 1em; }
.prose h2 { margin-top: 1.8em; font-size: clamp(22px, 2.2vw, 30px); }
.prose h3 { margin-top: 1.6em; }
.prose a { color: var(--cyan); border-bottom: 1px solid rgba(43, 227, 210, 0.42); }
.prose a:hover { border-bottom-color: var(--cyan); }
.prose ul, .prose ol { padding-left: 1.2em; }
.prose li { list-style: none; position: relative; padding-left: 0.2em; }
.prose li::before {
  content: "";
  position: absolute;
  left: -0.9em;
  top: 0.78em;
  width: 6px;
  height: 6px;
  background: var(--line);
  transform: rotate(45deg);
}

.link {
  position: relative;
  display: inline-block;
  color: var(--cyan);
}

.link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--t) var(--ease);
}

.link:hover::after,
.link:focus-visible::after { transform: scaleX(1); }

/* ---------- 5. 外壳与栅格 ---------- */
.wrap {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: clamp(46px, 6vw, 100px); }

.band { padding-block: clamp(48px, 6.5vw, 104px); }
.band--ink { background: var(--ink); }

.band--paper {
  background: var(--paper);
  color: var(--paper-ink);
}

.band--paper h1, .band--paper h2, .band--paper h3, .band--paper h4 { color: var(--paper-ink); }
.band--paper .lede, .band--paper .prose { color: var(--paper-body); }
.band--paper .eyebrow { color: #0E8E82; }
.band--paper .card { background: #FFFFFF; border-color: #D8E0F2; }
.band--paper .stat { border-top-color: #D8E0F2; }
.band--paper .stat__num { color: #A96A11; }
.band--paper .stat__label { color: var(--paper-body); }
.band--paper .section-head { border-bottom-color: #D8E0F2; }
.band--paper .media-frame { border-color: #D8E0F2; }

.grid {
  display: grid;
  gap: clamp(16px, 2.2vw, 30px);
}

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

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

.section-head {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: clamp(18px, 4vw, 60px);
  align-items: end;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
}

.section-head__note {
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 6. 面包屑 ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.crumbs a { color: var(--muted); transition: color var(--t) var(--ease); }
.crumbs a:hover { color: var(--cyan); }
.crumbs__sep { color: var(--line); }
.crumbs [aria-current="page"] { color: var(--text); }

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 13px 22px;
  border: 1px solid transparent;
  border-radius: 6px;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0.01em;
  text-align: center;
  transition:
    background-color var(--t) var(--ease),
    border-color var(--t) var(--ease),
    color var(--t) var(--ease),
    transform 120ms var(--ease);
}

.btn:active { transform: translateY(1px); }

.btn--primary { background: var(--amber); color: #24160A; }
.btn--primary:hover { background: #FFC470; }

.btn--cyan { background: var(--cyan); color: #062622; }
.btn--cyan:hover { background: #5EEADE; }

.btn--ghost { background: transparent; border-color: var(--line); color: var(--text); }
.btn--ghost:hover { border-color: var(--cyan); color: var(--cyan); }

.btn--sm { padding: 9px 14px; font-size: 13px; }
.btn--block { width: 100%; }

/* ---------- 8. 标记 / 卡片 / 数据 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: 0.08em;
  color: var(--muted);
  white-space: nowrap;
}

.tag--cyan { color: var(--cyan); border-color: rgba(43, 227, 210, 0.42); background: rgba(43, 227, 210, 0.08); }
.tag--amber { color: var(--amber); border-color: rgba(255, 179, 82, 0.42); background: rgba(255, 179, 82, 0.08); }
.tag--green { color: var(--green); border-color: rgba(99, 230, 164, 0.42); background: rgba(99, 230, 164, 0.08); }
.tag--coral { color: var(--coral); border-color: rgba(255, 122, 107, 0.42); background: rgba(255, 122, 107, 0.08); }

.card {
  padding: clamp(18px, 2vw, 28px);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  transition:
    border-color var(--t) var(--ease),
    background-color var(--t) var(--ease),
    transform var(--t) var(--ease);
}

.card:hover {
  border-color: var(--cyan);
  background: rgba(43, 227, 210, 0.05);
  transform: translateY(-2px);
}

.glass {
  background: var(--glass);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--r-md);
}

.stat {
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 2.6vw, 34px);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--amber);
}

.stat__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* ---------- 9. 图片容器基础规则 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background-color: rgba(7, 14, 32, 0.86);
  background-image:
    linear-gradient(135deg, rgba(43, 227, 210, 0.12), transparent 58%),
    repeating-linear-gradient(0deg, rgba(36, 52, 94, 0.55) 0 1px, transparent 1px 34px),
    repeating-linear-gradient(90deg, rgba(36, 52, 94, 0.55) 0 1px, transparent 1px 34px);
}

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 180ms var(--ease);
}

.media-frame:hover img { transform: scale(1.02); }

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame__note {
  position: absolute;
  left: 14px;
  bottom: 12px;
  padding: 4px 9px;
  border-radius: var(--r-sm);
  background: rgba(7, 14, 32, 0.78);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--muted-soft);
}

.figure-cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  letter-spacing: 0.04em;
  color: var(--muted);
}

/* ---------- 10. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: rgba(7, 14, 32, 0.94);
  border-bottom: 1px solid var(--line);
}

.skip-link {
  position: absolute;
  top: 8px;
  left: 8px;
  z-index: 200;
  padding: 12px 18px;
  border-radius: 6px;
  background: var(--cyan);
  color: #062622;
  font-size: 14px;
  font-weight: 600;
  line-height: 1;
  transform: translateY(-180%);
  transition: transform 140ms var(--ease);
}

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

.hud {
  position: relative;
  max-width: var(--shell);
  margin-inline: auto;
  border-inline: 1px solid var(--line);
}

.hud__rail {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 30px);
  min-height: 58px;
  padding: 9px var(--gutter);
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  flex: 0 0 auto;
}

.brand__mark {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--text);
  transition: color var(--t) var(--ease);
}

.brand__sub {
  padding-left: 10px;
  border-left: 1px solid var(--line);
  font-family: var(--font-serif);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: var(--muted);
}

.brand:hover .brand__mark { color: var(--cyan); }

.brand--foot .brand__mark { font-size: 23px; }

.hud__coord {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.hud__coord-key { color: var(--amber); }
.hud__coord-val { color: var(--muted); }

.hud__actions {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
}

.hud__entry { color: var(--green); }

.index-trigger {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 15px;
  border: 1px solid var(--line);
  border-radius: 6px;
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  line-height: 1;
  color: var(--text);
  transition:
    border-color var(--t) var(--ease),
    color var(--t) var(--ease),
    background-color var(--t) var(--ease);
}

.index-trigger:hover { border-color: var(--cyan); color: var(--cyan); }

.index-trigger__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(43, 227, 210, 0.16);
}

.index-trigger[aria-expanded="true"] {
  border-color: var(--cyan);
  background: rgba(43, 227, 210, 0.10);
  color: var(--cyan);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 10px 13px;
  border: 1px solid var(--line);
  border-radius: 6px;
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  line-height: 1;
  color: var(--text);
  transition: border-color var(--t) var(--ease), color var(--t) var(--ease);
}

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

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 16px;
  height: 2px;
  background: currentColor;
  transition: background-color var(--t) var(--ease);
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background: currentColor;
  transition: transform var(--t) var(--ease), top var(--t) var(--ease);
}

.nav-toggle__bars::before { top: -5px; }
.nav-toggle__bars::after { top: 5px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { top: 0; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { top: 0; transform: rotate(-45deg); }

/* 框架式导航导轨 */
.framenav { border-top: 1px solid var(--line); }

.framenav__list {
  display: flex;
  align-items: stretch;
}

.framenav__item {
  flex: 1 1 0;
  min-width: 0;
  border-left: 1px solid var(--line);
}

.framenav__item:first-child { border-left: 0; }

.framenav__link {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 15px clamp(12px, 1.2vw, 20px);
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.2;
  color: var(--muted-soft);
  transition: color var(--t) var(--ease), background-color var(--t) var(--ease);
}

.framenav__link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--amber));
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 160ms var(--ease);
}

.framenav__link:hover {
  color: var(--text);
  background: rgba(43, 227, 210, 0.06);
}

.framenav__link:hover::after { transform: scaleX(1); }

.framenav__link[aria-current="page"] {
  color: var(--cyan);
  background: rgba(43, 227, 210, 0.09);
}

.framenav__link[aria-current="page"]::after { transform: scaleX(1); }

.framenav__label {
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.framenav__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.framenav__link[aria-current="page"] .framenav__num { color: var(--amber); }

.hud__progress {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--amber));
  transform: scaleX(0);
  transform-origin: left center;
  pointer-events: none;
}

/* ---------- 11. 站内索引抽屉 ---------- */
.index-scrim {
  position: fixed;
  inset: 0;
  z-index: 110;
  background: rgba(4, 8, 20, 0.66);
  opacity: 0;
  visibility: hidden;
  transition: opacity 180ms var(--ease), visibility 180ms;
}

.index-scrim[data-open] { opacity: 1; visibility: visible; }

.index-drawer {
  position: fixed;
  top: 0;
  right: 0;
  z-index: 120;
  display: flex;
  flex-direction: column;
  gap: 16px;
  width: min(430px, 94vw);
  height: 100%;
  padding: 26px var(--gutter) 30px;
  background: rgba(7, 14, 32, 0.97);
  border-left: 1px solid var(--line);
  box-shadow: -30px 0 60px rgba(4, 8, 20, 0.5);
  transform: translateX(104%);
  visibility: hidden;
  transition: transform 190ms var(--ease), visibility 190ms;
}

.index-drawer[data-open] { transform: none; visibility: visible; }

.index-drawer__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.index-drawer__title {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0.02em;
  color: var(--text);
}

.index-drawer__close {
  width: 36px;
  height: 36px;
  border: 1px solid var(--line);
  border-radius: 6px;
  font-size: 18px;
  line-height: 1;
  color: var(--muted);
  transition: border-color var(--t) var(--ease), color var(--t) var(--ease);
}

.index-drawer__close:hover { border-color: var(--coral); color: var(--coral); }

.index-drawer__hint {
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.8;
  color: var(--muted);
}

kbd {
  display: inline-block;
  min-width: 20px;
  padding: 2px 6px;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  background: rgba(255, 255, 255, 0.06);
  font-family: var(--font-mono);
  font-size: 11px;
  text-align: center;
  color: var(--text);
}

.index-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0 -6px;
  padding: 0 6px;
  overflow-y: auto;
}

.index-list__link {
  display: grid;
  grid-template-columns: 36px minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  padding: 13px 12px;
  border: 1px solid transparent;
  border-radius: 6px;
  color: var(--muted-soft);
  transition:
    background-color var(--t) var(--ease),
    border-color var(--t) var(--ease),
    color var(--t) var(--ease);
}

.index-list__link:hover,
.index-list__link:focus-visible {
  background: rgba(43, 227, 210, 0.08);
  border-color: rgba(43, 227, 210, 0.42);
  color: var(--text);
}

.index-list__link[aria-current="page"] {
  border-color: var(--cyan);
  background: rgba(43, 227, 210, 0.10);
  color: var(--cyan);
}

.index-list__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.index-list__label { font-size: 15px; font-weight: 500; }

.index-list__route {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.index-drawer__foot {
  margin-top: auto;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.8;
  color: var(--muted);
}

.is-index-open { overflow: hidden; }

/* ---------- 12. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(60px, 8vw, 120px);
  background: var(--ink);
}

.site-footer::before {
  content: "";
  display: block;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), rgba(43, 227, 210, 0.08) 42%, var(--amber));
}

.foot {
  max-width: var(--shell);
  margin-inline: auto;
  padding: clamp(38px, 4.6vw, 68px) var(--gutter) 0;
  border-inline: 1px solid var(--line);
}

.foot__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 14px 32px;
  padding-bottom: clamp(24px, 3.2vw, 44px);
  border-bottom: 1px solid var(--line);
}

.foot__tagline {
  flex: 1 1 300px;
  max-width: 46ch;
  font-size: 15px;
  line-height: 1.7;
  color: var(--muted-soft);
}

.foot__stamp {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan);
}

.foot__grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 44px);
  padding-block: clamp(28px, 3.8vw, 54px);
}

.foot-col__title {
  margin-bottom: 14px;
  font-family: var(--font-serif);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--amber);
}

.foot-col__list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.foot-col__list + .foot-col__list { margin-top: 16px; }

.foot-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 5px 0;
  font-size: 14.5px;
  color: #B9C6E6;
  transition: color var(--t) var(--ease);
}

.foot-link::before {
  content: "";
  flex: 0 0 auto;
  width: 5px;
  height: 5px;
  background: var(--line);
  transform: rotate(45deg);
  transition: background-color var(--t) var(--ease);
}

.foot-link:hover { color: var(--text); }
.foot-link:hover::before { background: var(--cyan); }
.foot-link[aria-current="page"] { color: var(--cyan); }

.foot-col__list--plain li {
  padding: 5px 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

.foot-col--legal { border-left: 1px solid var(--line); padding-left: clamp(14px, 2vw, 28px); }

.foot__base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 30px;
  padding-block: 20px 30px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--muted);
}

.foot__icp { color: var(--muted-soft); }
.foot__base-note { margin-left: auto; }

/* ---------- 13. 响应式 ---------- */
@media (max-width: 1180px) {
  .hud__entry { display: none; }
}

@media (max-width: 980px) {
  .span-4 { grid-column: span 6; }
  .span-5 { grid-column: span 12; }
  .span-7, .span-8 { grid-column: span 12; }

  .section-head { grid-template-columns: minmax(0, 1fr); align-items: start; gap: 12px; }

  .foot__grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .foot-col--legal { border-left: 0; padding-left: 0; }
  .foot__base-note { margin-left: 0; }
}

@media (max-width: 900px) {
  .hud__coord,
  .hud__entry { display: none; }

  .nav-toggle { display: inline-flex; }

  .framenav { overflow: hidden; }

  .framenav__list {
    flex-direction: column;
    max-height: 0;
    transition: max-height 220ms var(--ease);
  }

  .framenav[data-open] .framenav__list {
    max-height: min(70vh, 480px);
    overflow-y: auto;
  }

  .framenav__item {
    flex: 0 0 auto;
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  .framenav__item:first-child { border-top: 0; }

  .framenav__link { padding: 16px var(--gutter); }

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

@media (max-width: 760px) {
  .foot { padding-inline: var(--gutter); }
}

@media (max-width: 640px) {
  body { font-size: 15.5px; }

  .span-4, .span-6 { grid-column: span 12; }

  .hud__rail { min-height: 54px; padding-inline: var(--gutter); gap: 10px; }

  .brand__sub { display: none; }

  .hud__actions .btn--sm { display: none; }

  .foot__grid { grid-template-columns: minmax(0, 1fr); }
  .foot__stamp { margin-left: 0; }

  .media-frame { aspect-ratio: 4 / 3; }
}

/* ---------- 14. 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0ms !important;
    scroll-behavior: auto !important;
  }

  .media-frame:hover img { transform: none; }
  .card:hover { transform: none; }
  .btn:active { transform: none; }
}