/* =========================================================
   28体育游戏 · 全站共享样式 /assets/site.css
   框架式导航 · 球场档案夹 · 深色数据底板
   ========================================================= */

/* ---------- 1. 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}
body, h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd, ul, ol { margin: 0; }
ul, ol { padding: 0; }
ul:not([class]), ol:not([class]) { padding-left: 1.2em; }
img, svg, video, canvas { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
table { border-collapse: collapse; }

/* ---------- 2. 设计令牌 ---------- */
:root {
  --green: #0A5C36;
  --green-hi: #0d7043;
  --green-deep: #063D24;
  --orange: #FF6B35;
  --orange-soft: #FFA06B;
  --ink: #111111;
  --graphite: #1C1C1C;
  --silver: #C0C0C0;
  --paper: #F4F1EA;
  --paper-ink: #1A1A1A;
  --wine: #6E1F2B;
  --indigo: #17313F;
  --cyan: #4FD1C5;

  --text: #E8E6E1;
  --text-dim: #C0C0C0;
  --text-mute: #8C8C88;
  --line: rgba(192, 192, 192, 0.26);
  --line-strong: rgba(192, 192, 192, 0.55);

  --rail-w: 224px;
  --toprail-h: 54px;
  --s1: 24px;
  --s2: 40px;
  --s3: 72px;
  --r: 2px;

  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei",
    system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, "IBM Plex Mono", "SFMono-Regular", Menlo, Consolas,
    "Courier New", monospace;

  --ease: cubic-bezier(0.2, 0.6, 0.2, 1);
}

/* ---------- 3. 基础排版（中文优先） ---------- */
body {
  background: var(--ink);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  padding-top: var(--toprail-h);
}

h1, h2, h3, h4 {
  color: var(--paper);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: 0.6em;
}
h1 { font-size: 56px; }
h2 { font-size: 40px; }
h3 { font-size: 28px; }
h4 { font-size: 20px; }
p { line-height: 1.75; }

.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
  font-variant-numeric: tabular-nums;
}
.text-dim { color: var(--text-dim); }
.text-mute { color: var(--text-mute); }

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  color: var(--orange);
  letter-spacing: 0.02em;
}
.num--lg { font-size: 40px; line-height: 1; }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 4. 焦点与可访问性 ---------- */
:focus-visible {
  outline: 3px solid var(--orange);
  outline-offset: 2px;
}

.skip-link {
  position: fixed;
  top: 10px; left: 10px;
  z-index: 300;
  padding: 10px 16px;
  background: var(--orange);
  color: var(--paper-ink);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.04em;
  border-radius: var(--r);
  transform: translateY(-220%);
  transition: transform 0.2s var(--ease);
}
.skip-link:focus { transform: none; }

/* ---------- 5. 容器与网格 ---------- */
.wrap {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 var(--s1);
}
.stack > * + * { margin-top: var(--s1); }
.divider { height: 1px; background: var(--line); border: 0; margin: var(--s1) 0; }

.grid { display: grid; gap: var(--s1); }
@media (min-width: 768px) {
  .grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (min-width: 1024px) {
  .grid--7-5 { grid-template-columns: 7fr 5fr; }
  .grid--5-7 { grid-template-columns: 5fr 7fr; }
  .grid--8-4 { grid-template-columns: 8fr 4fr; }
}

/* ---------- 6. 章节骨架与标签 ---------- */
.section { padding: var(--s3) 0; }
.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 16px;
  padding-bottom: 16px;
  margin-bottom: var(--s2);
  border-bottom: 1px solid var(--line);
}
.section__head h2 { margin-bottom: 0; }

.spine {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--orange);
  text-transform: uppercase;
}
.spine::before {
  content: "";
  width: 16px; height: 3px;
  background: currentColor;
  display: inline-block;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--silver);
}
.eyebrow::before {
  content: "";
  width: 4px; height: 14px;
  background: var(--orange);
  display: inline-block;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--silver);
  background: rgba(192, 192, 192, 0.07);
  border: 1px solid var(--line-strong);
  border-radius: var(--r);
  transition: transform 0.2s var(--ease), border-color 0.2s var(--ease),
    color 0.2s var(--ease), background-color 0.2s var(--ease);
}
.tag--orange { color: var(--orange); border-color: rgba(255, 107, 53, 0.5); background: rgba(255, 107, 53, 0.1); }
.tag--green { color: #8fd7b0; border-color: rgba(10, 92, 54, 0.9); background: rgba(10, 92, 54, 0.35); }
.tag--wine { color: #e2a7b0; border-color: rgba(110, 31, 43, 0.9); background: rgba(110, 31, 43, 0.4); }
.tag--silver { color: var(--silver); border-color: var(--line-strong); }
.tag:hover { transform: translateY(-2px); }

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--paper);
  background: var(--graphite);
  border: 1px solid var(--line);
  border-radius: var(--r);
  transition: transform 0.2s var(--ease), background-color 0.2s var(--ease),
    color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }
.btn--primary { background: var(--green); border-color: rgba(192, 192, 192, 0.35); }
.btn--primary:hover { background: var(--green-hi); }
.btn--orange { background: var(--orange); border-color: var(--orange); color: var(--paper-ink); }
.btn--orange:hover { background: var(--orange-soft); border-color: var(--orange-soft); }
.btn--ghost { background: transparent; border-color: var(--line-strong); color: var(--text); }
.btn--ghost:hover { color: var(--orange); border-color: var(--orange); }
.btn--sm { padding: 7px 14px; font-size: 13px; }
.btn--block { width: 100%; }

/* ---------- 8. 资料卡 / 纸张叠层 ---------- */
.card {
  position: relative;
  padding: var(--s1);
  background: var(--graphite);
  border: 1px solid var(--line);
  border-radius: var(--r);
}
.card__title { font-size: 20px; margin-bottom: 12px; }
.card--paper {
  background: var(--paper);
  color: var(--paper-ink);
  border-color: rgba(26, 26, 26, 0.16);
  box-shadow: 8px 8px 0 -1px rgba(6, 61, 36, 0.9), 8px 8px 0 0 rgba(192, 192, 192, 0.2);
}
.card--paper :is(h1, h2, h3, h4) { color: var(--paper-ink); }
.card--paper :is(.text-dim, .text-mute) { color: #4a4a46; }
.card--green {
  background: linear-gradient(155deg, rgba(10, 92, 54, 0.95) 0%, rgba(6, 61, 36, 0.98) 100%);
  border-color: rgba(192, 192, 192, 0.3);
}
.card--indigo {
  background: linear-gradient(155deg, #17313F 0%, #0e1f28 100%);
  border-color: rgba(79, 209, 197, 0.24);
}
.card--wine {
  background: linear-gradient(155deg, #6E1F2B 0%, #3b1018 100%);
  border-color: rgba(192, 192, 192, 0.24);
}
.card--wine .num { color: var(--orange-soft); }

/* ---------- 9. 可展开内容组 ---------- */
.disclosure {
  background: var(--graphite);
  border: 1px solid var(--line);
  border-radius: var(--r);
}
.disclosure + .disclosure { margin-top: 10px; }
.disclosure__btn {
  width: 100%;
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 18px;
  text-align: left;
  color: var(--text);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: 0.02em;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease);
}
.disclosure__btn:hover { color: var(--orange); background: rgba(255, 107, 53, 0.06); }
.disclosure__num { font-family: var(--font-mono); font-size: 12px; color: var(--orange); letter-spacing: 0.08em; }
.disclosure__icon {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--silver);
  line-height: 1;
}
.disclosure__panel {
  display: none;
  padding: 14px 18px 20px;
  border-top: 1px solid var(--line);
  color: var(--text-dim);
  font-size: 15px;
}
.disclosure[data-open] .disclosure__panel { display: block; }
.disclosure[data-open] .disclosure__btn { color: var(--paper); }
.disclosure[data-open] .disclosure__icon { color: var(--orange); }

/* ---------- 10. 图片容器（页面阶段放置占位图） ---------- */
.media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: linear-gradient(140deg, var(--indigo) 0%, var(--green) 100%);
}
.media > img { width: 100%; height: 100%; object-fit: cover; }
.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--21x9 { aspect-ratio: 21 / 9; }
.media__label {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: rgba(244, 241, 234, 0.86);
  background: linear-gradient(180deg, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 0.66) 100%);
}

/* ---------- 11. 面包屑 / 表格 / 长文 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: var(--s1);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--text-mute);
  list-style: none;
  padding-left: 0;
}
.breadcrumb a { color: var(--text-dim); }
.breadcrumb a:hover { color: var(--orange); }
.breadcrumb li + li::before { content: "/"; margin-right: 8px; color: var(--text-mute); }

.data-table { width: 100%; font-size: 15px; }
.data-table th, .data-table td {
  padding: 10px 12px;
  text-align: left;
  border-bottom: 1px solid var(--line);
}
.data-table thead th {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--silver);
  background: rgba(192, 192, 192, 0.07);
}
.data-table tbody tr:nth-child(odd) { background: rgba(244, 241, 234, 0.03); }

.prose { max-width: 38em; font-size: 17px; line-height: 1.75; }
.prose p + p { margin-top: 1em; }
.prose h2, .prose h3 { margin-top: 1.4em; }
.prose ul, .prose ol { padding-left: 1.3em; }
.prose li + li { margin-top: 0.4em; }
.prose a { color: var(--orange); border-bottom: 1px solid rgba(255, 107, 53, 0.4); }
.prose a:hover { border-bottom-color: var(--orange); }

/* ---------- 12. 头部：框架式导航 ---------- */
.site-header { position: relative; z-index: 80; }

.toprail {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--toprail-h);
  z-index: 90;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 18px;
  background: linear-gradient(180deg, #161616 0%, #0c0c0c 100%);
  border-bottom: 1px solid var(--line);
}
.toprail__status {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--silver);
  white-space: nowrap;
  overflow: hidden;
}
.toprail__phase { color: var(--text); font-weight: 600; }
.toprail__meta { color: var(--text-mute); }
.toprail__div { color: var(--text-mute); }
.pulse {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--orange);
  flex: none;
  animation: pulse 2.4s var(--ease) infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(255, 107, 53, 0.55); }
  70% { box-shadow: 0 0 0 10px rgba(255, 107, 53, 0); }
  100% { box-shadow: 0 0 0 0 rgba(255, 107, 53, 0); }
}
.toprail__progress {
  position: absolute;
  left: 0; right: 0; bottom: -1px;
  height: 2px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--green) 0%, var(--orange) 60%, var(--orange-soft) 100%);
}

.quicknav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 4px;
}
.quicknav__link {
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  border: 1px solid transparent;
  border-radius: var(--r);
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease),
    background-color 0.2s var(--ease);
}
.quicknav__link:hover {
  color: var(--orange);
  border-color: rgba(255, 107, 53, 0.45);
  background: rgba(255, 107, 53, 0.08);
}

/* 品牌 */
.brand { display: flex; align-items: center; gap: 12px; color: var(--paper); }
.brand__mark {
  display: grid;
  place-items: center;
  width: 46px; height: 46px;
  flex: none;
  background: var(--orange);
  color: var(--paper-ink);
  font-family: var(--font-mono);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0;
  border-radius: var(--r);
}
.brand__text { display: flex; flex-direction: column; line-height: 1.15; }
.brand__name { font-size: 17px; font-weight: 800; letter-spacing: 0.06em; }
.brand__sub {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.24em;
  color: rgba(244, 241, 234, 0.62);
}
.brand--compact { display: none; gap: 10px; }
.brand--compact .brand__mark { width: 32px; height: 32px; font-size: 13px; }
.brand--compact .brand__name { font-size: 15px; }
.brand--foot .brand__mark { width: 42px; height: 42px; font-size: 17px; }

/* 左边界导航 */
.leftrail {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  width: var(--rail-w);
  z-index: 95;
  display: flex;
  flex-direction: column;
  gap: 22px;
  padding: 20px 18px 22px;
  overflow-y: auto;
  overflow-x: hidden;
  background:
    linear-gradient(180deg, rgba(10, 92, 54, 0.55) 0%, rgba(6, 61, 36, 0.92) 55%, rgba(4, 41, 26, 1) 100%),
    repeating-linear-gradient(0deg, rgba(192, 192, 192, 0.06) 0 1px, transparent 1px 26px),
    var(--green-deep);
  border-right: 1px solid rgba(192, 192, 192, 0.4);
}
.leftrail__foot {
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-top: 18px;
  border-top: 1px solid rgba(192, 192, 192, 0.22);
}
.leftrail__note {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-align: center;
  color: rgba(244, 241, 234, 0.55);
}

.site-nav { display: flex; flex-direction: column; }
.site-nav__title {
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: rgba(244, 241, 234, 0.55);
}
.site-nav__list { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; }
.site-nav__link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 10px 11px 14px;
  font-size: 15px;
  font-weight: 600;
  color: rgba(244, 241, 234, 0.78);
  border-left: 3px solid transparent;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease),
    border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.site-nav__link:hover {
  color: var(--paper);
  background: rgba(17, 17, 17, 0.34);
  border-left-color: var(--orange);
  transform: translateX(2px);
}
.site-nav__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: rgba(244, 241, 234, 0.45);
}
.site-nav__link[aria-current="page"] {
  color: #ffffff;
  background: rgba(17, 17, 17, 0.52);
  border-left-color: var(--orange);
}
.site-nav__link[aria-current="page"] .site-nav__num { color: var(--orange); }

/* 移动端按钮与遮罩（桌面隐藏） */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  padding: 8px 12px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--paper);
  background: var(--green);
  border: 1px solid rgba(192, 192, 192, 0.45);
  border-radius: var(--r);
}
.nav-toggle__bars { display: inline-flex; flex-direction: column; gap: 3px; width: 14px; }
.nav-toggle__bars span { display: block; height: 2px; width: 100%; background: currentColor; }
.nav-toggle__bars span:nth-child(2) { width: 70%; }
.site-header[data-open] .nav-toggle__bars span:nth-child(2) { width: 100%; }

.nav-close {
  display: none;
  align-self: flex-start;
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--paper);
  border: 1px solid rgba(244, 241, 234, 0.4);
  border-radius: var(--r);
}
.nav-close:hover { border-color: var(--orange); color: var(--orange); }

.nav-scrim { display: none; }

/* ---------- 13. 页脚：档案夹叠层 ---------- */
.site-footer {
  position: relative;
  margin-top: var(--s3);
  padding: var(--s3) 0 var(--s1);
  background: linear-gradient(180deg, var(--green-deep) 0%, #04291a 100%);
  border-top: 1px solid rgba(192, 192, 192, 0.42);
  color: var(--text);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 6px;
  background-image: repeating-linear-gradient(
    90deg,
    rgba(192, 192, 192, 0.42) 0 8px,
    transparent 8px 20px
  );
  opacity: 0.55;
}
.foot-wrap { width: 100%; max-width: 1240px; margin: 0 auto; padding: 0 var(--s1); }
.foot-grid { display: grid; gap: var(--s1); grid-template-columns: 1fr; }

.foot-brand { display: flex; flex-direction: column; gap: 14px; }
.foot-brand__line { font-size: 15px; line-height: 1.7; color: rgba(232, 230, 225, 0.86); max-width: 30em; }
.foot-brand__meta {
  font-size: 11px;
  letter-spacing: 0.14em;
  color: rgba(192, 192, 192, 0.72);
}

.foot-col {
  position: relative;
  padding: 18px 16px 18px 20px;
  background: rgba(17, 17, 17, 0.44);
  border: 1px solid var(--line);
  border-radius: var(--r);
  box-shadow: 7px 7px 0 -1px rgba(4, 41, 26, 0.9), 7px 7px 0 0 rgba(192, 192, 192, 0.16);
}
.foot-col__title {
  display: inline-flex;
  align-items: center;
  margin-bottom: 14px;
  padding: 4px 10px 4px 11px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.2em;
  color: var(--paper);
  background: var(--col-tint, rgba(192, 192, 192, 0.12));
  border-left: 3px solid var(--col-accent, var(--silver));
  border-radius: 1px;
}
.foot-col__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 9px;
  font-size: 14px;
}
.foot-col__list a {
  color: var(--text);
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.foot-col__list a:hover { color: var(--orange); border-bottom-color: rgba(255, 107, 53, 0.6); }
.foot-col__muted { font-size: 12px; color: var(--text-mute); }

.foot-col--nav { --col-accent: var(--orange); --col-tint: rgba(255, 107, 53, 0.16); }
.foot-col--rules { --col-accent: #a8434f; --col-tint: rgba(110, 31, 43, 0.5); }
.foot-col--contact { --col-accent: var(--silver); --col-tint: rgba(23, 49, 63, 0.8); }
.foot-col--icp { --col-accent: var(--orange-soft); --col-tint: rgba(192, 192, 192, 0.14); }

.contact-line {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 13px;
}
.contact-line__label {
  min-width: 2.4em;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--text-mute);
}
.contact-line__value { flex: 1 1 auto; min-width: 0; word-break: break-all; }
.copy-btn {
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--silver);
  border: 1px solid var(--line);
  border-radius: var(--r);
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease),
    background-color 0.2s var(--ease);
}
.copy-btn:hover { color: var(--orange); border-color: rgba(255, 107, 53, 0.5); }
.copy-btn.is-done {
  color: var(--paper-ink);
  background: var(--orange);
  border-color: var(--orange);
}

.foot-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-top: var(--s2);
  padding-top: var(--s1);
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--text-mute);
}
.foot-base__copy { font-family: var(--font-mono); letter-spacing: 0.06em; }
.foot-base__note { max-width: 34em; }

.to-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 110;
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--paper-ink);
  background: var(--orange);
  border: 1px solid rgba(26, 26, 26, 0.8);
  border-radius: var(--r);
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: opacity 0.2s var(--ease), transform 0.2s var(--ease),
    background-color 0.2s var(--ease);
}
.to-top.is-visible { opacity: 1; transform: none; pointer-events: auto; }
.to-top:hover { background: var(--orange-soft); }

/* ---------- 14. 桌面框架（≥1024px） ---------- */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }
  .toprail { left: var(--rail-w); }
  body::after {
    content: "";
    position: fixed;
    top: var(--toprail-h);
    right: 0;
    bottom: 0;
    width: 1px;
    background: var(--line);
    pointer-events: none;
    z-index: 50;
  }
}

/* ---------- 15. 平板（640–1023px） ---------- */
@media (min-width: 640px) {
  .foot-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

/* ---------- 16. 移动端（<1024px）：抽屉 + 底部快捷条 ---------- */
@media (max-width: 1023.98px) {
  body { padding-bottom: 64px; }

  .toprail { padding: 0 14px; gap: 12px; }
  .toprail__status { display: none; }
  .brand--compact { display: flex; }
  .nav-toggle { display: inline-flex; }

  .leftrail {
    width: min(84vw, 320px);
    z-index: 120;
    transform: translateX(-102%);
    visibility: hidden;
    box-shadow: 16px 0 44px rgba(0, 0, 0, 0.55);
    transition: transform 0.2s var(--ease), visibility 0.2s var(--ease);
  }
  .site-header[data-open] .leftrail { transform: none; visibility: visible; }
  .nav-close { display: inline-flex; }

  .nav-scrim {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 115;
    background: rgba(0, 0, 0, 0.6);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s var(--ease);
  }
  .site-header[data-open] .nav-scrim { opacity: 1; pointer-events: auto; }

  .quicknav {
    position: fixed;
    left: 0; right: 0; bottom: 0;
    z-index: 90;
    margin: 0;
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0;
    padding: 0;
    height: 60px;
    background: #0d0d0d;
    border-top: 1px solid var(--line);
  }
  .quicknav__link {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    padding: 0;
    font-size: 13px;
    color: var(--text-dim);
    border: 0;
    border-radius: 0;
  }
  .quicknav__link + .quicknav__link { border-left: 1px solid var(--line); }
  .quicknav__link:hover,
  .quicknav__link:focus-visible { background: rgba(255, 107, 53, 0.1); color: var(--orange); }

  .to-top { right: 14px; bottom: 76px; }

  h1 { font-size: 34px; }
  h2 { font-size: 30px; }
  h3 { font-size: 23px; }
  h4 { font-size: 18px; }
  body { font-size: 16px; }
}

/* ---------- 17. 大屏页脚五栏 ---------- */
@media (min-width: 1024px) {
  .foot-grid { grid-template-columns: 1.5fr 0.9fr 0.8fr 1.5fr 0.9fr; }
}

/* ---------- 18. 动效降级 ---------- */
@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;
  }
  .btn:hover, .tag:hover, .site-nav__link:hover { transform: none; }
}