/* ==========================================================================
   九龙体育 · 全站共享样式 /site.css
   夜场数据刊物：墨蓝基调 + 极细边界 + 等宽数字
   ========================================================================== */

/* ---------- reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
}

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

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

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

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

a { color: inherit; }

table { border-collapse: collapse; }
th, td { text-align: left; }

/* ---------- 变量 ---------- */
:root {
  --c-ink: #0C1A2E;
  --c-night: #16294A;
  --c-paper: #F4F1E8;
  --c-white: #FFFFFF;
  --c-gold: #E8B23A;
  --c-gold-soft: #F7E3B0;
  --c-grass: #2F8F5B;
  --c-orange: #F07A2A;
  --c-orange-deep: #A8461A;
  --c-brick: #B5482F;
  --c-moss: #6E7D5B;
  --c-clay: #C08A6A;
  --c-text: #1B2430;
  --c-muted: #5B6472;

  --c-line: rgba(27, 36, 48, 0.14);
  --c-line-strong: rgba(27, 36, 48, 0.26);
  --c-line-dark: rgba(244, 241, 232, 0.16);
  --c-line-dark-soft: rgba(244, 241, 232, 0.10);

  --font-display: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --font-ui: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, "Courier New", monospace;

  --wrap: 1200px;
  --gutter: clamp(16px, 4vw, 48px);
  --radius: 2px;
  --shadow-1: 0 1px 2px rgba(12, 26, 46, 0.06), 0 10px 28px -20px rgba(12, 26, 46, 0.42);
  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
  --nav-break: 880px;
}

/* ---------- 中文排版基准 ---------- */
body {
  background-color: var(--c-paper);
  color: var(--c-text);
  font-family: var(--font-ui);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: 0.01em;
}

.mono,
.num,
time,
[data-num] {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0;
}

/* ---------- 可访问性 ---------- */
:focus-visible {
  outline: 2px solid var(--c-gold);
  outline-offset: 2px;
  border-radius: 2px;
}

.visually-hidden {
  position: absolute !important;
  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;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 50%;
  z-index: 300;
  transform: translate(-50%, -220%);
  padding: 11px 20px;
  background: var(--c-gold);
  color: var(--c-ink);
  font-family: var(--font-ui);
  font-size: 15px;
  font-weight: 700;
  text-decoration: none;
  border-radius: var(--radius);
  box-shadow: var(--shadow-1);
  transition: transform 0.18s var(--ease);
}

.skip-link:focus {
  transform: translate(-50%, 0);
}

/* ==========================================================================
   页头
   ========================================================================== */
.site-header {
  position: relative;
  z-index: 30;
  background-color: var(--c-ink);
  color: var(--c-paper);
  overflow: hidden;
  border-bottom: 1px solid rgba(232, 178, 58, 0.22);
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(58% 130% at 50% -34%, rgba(232, 178, 58, 0.18), transparent 64%),
    radial-gradient(46% 96% at 8% 128%, rgba(22, 41, 74, 0.95), transparent 72%);
  pointer-events: none;
}

.header-inner,
.nav-bar {
  position: relative;
  z-index: 1;
}

.header-inner {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(22px, 3.4vw, 34px) var(--gutter) 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.masthead-eyebrow {
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.36em;
  text-indent: 0.36em;
  color: rgba(244, 241, 232, 0.52);
  margin-bottom: 14px;
}

.masthead-logo {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(28px, 4.8vw, 52px);
  line-height: 1.14;
  color: var(--c-paper);
  text-decoration: none;
  transition: color 0.16s var(--ease);
}

.masthead-logo:hover { color: var(--c-gold-soft); }

.masthead-tagline {
  margin-top: 14px;
  font-size: 14px;
  letter-spacing: 0.08em;
  color: rgba(244, 241, 232, 0.66);
}

.header-rule {
  display: block;
  width: min(340px, 58%);
  height: 2px;
  margin-top: 22px;
  background-image: linear-gradient(90deg, transparent, var(--c-gold) 24%, var(--c-gold) 76%, transparent);
}

/* 导航条 */
.nav-bar {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.site-nav {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  padding: 14px 0 22px;
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 2px 6px;
}

.nav-link {
  display: inline-block;
  padding: 10px 14px 11px;
  font-family: var(--font-ui);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: rgba(244, 241, 232, 0.76);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.nav-link:hover {
  color: var(--c-paper);
  border-bottom-color: rgba(232, 178, 58, 0.5);
}

.nav-link[aria-current="page"] {
  color: var(--c-gold);
  border-bottom-color: var(--c-gold);
}

.index-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 12px;
}

.index-list a {
  display: inline-block;
  padding: 5px 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: rgba(244, 241, 232, 0.48);
  text-decoration: none;
  border-right: 1px solid var(--c-line-dark);
  transition: color 0.16s var(--ease);
}

.index-list li:last-child a { border-right: 0; }
.index-list a:hover { color: var(--c-gold-soft); }

.nav-cta { margin-top: 18px; }

/* 移动端开关 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  margin-top: 16px;
  padding: 10px 18px;
  background: rgba(232, 178, 58, 0.10);
  border: 1px solid rgba(232, 178, 58, 0.46);
  border-radius: 999px;
  color: var(--c-gold-soft);
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.10em;
  cursor: pointer;
  transition: background-color 0.16s var(--ease), border-color 0.16s var(--ease), color 0.16s var(--ease);
}

.nav-toggle:hover {
  background: rgba(232, 178, 58, 0.18);
  border-color: var(--c-gold);
  color: var(--c-gold);
}

.nav-toggle-icon {
  position: relative;
  display: inline-block;
  width: 16px;
  height: 10px;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  width: 100%;
  height: 1.5px;
  background: currentColor;
  transition: transform 0.18s var(--ease);
}

.nav-toggle-icon::before { transform: translateY(-4px); }
.nav-toggle-icon::after { transform: translateY(4px); }

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before { transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after { transform: rotate(-45deg); }

/* ==========================================================================
   页脚
   ========================================================================== */
.site-footer {
  background-color: var(--c-ink);
  color: rgba(244, 241, 232, 0.74);
  border-top: 2px solid var(--c-gold);
  font-size: 14px;
  line-height: 1.8;
}

.footer-inner {
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(38px, 5.6vw, 72px) var(--gutter) 38px;
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: 38px 32px;
  border-bottom: 1px solid var(--c-line-dark);
}

.footer-logo {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 700;
  color: var(--c-paper);
  text-decoration: none;
  transition: color 0.16s var(--ease);
}

.footer-logo:hover { color: var(--c-gold); }

.footer-desc {
  margin-top: 14px;
  max-width: 42ch;
  color: rgba(244, 241, 232, 0.58);
}

.footer-col-title {
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.20em;
  color: var(--c-gold);
  margin-bottom: 14px;
}

.footer-link-list {
  display: grid;
  gap: 9px;
}

.footer-link {
  color: rgba(244, 241, 232, 0.72);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.footer-link:hover {
  color: var(--c-gold-soft);
  border-bottom-color: rgba(232, 178, 58, 0.6);
}

.footer-meta {
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 26px var(--gutter) 46px;
  display: grid;
  gap: 8px;
  font-size: 13.5px;
  color: rgba(244, 241, 232, 0.58);
}

.footer-contact {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: rgba(244, 241, 232, 0.72);
}

.footer-hours { color: rgba(244, 241, 232, 0.52); }

.footer-legal {
  padding-left: 12px;
  border-left: 2px solid var(--c-brick);
  color: rgba(244, 241, 232, 0.62);
}

.footer-bottom {
  margin-top: 14px;
  padding-top: 18px;
  border-top: 1px solid var(--c-line-dark-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: rgba(244, 241, 232, 0.42);
}

/* ==========================================================================
   版面容器与分区
   ========================================================================== */
.container {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: clamp(46px, 6.6vw, 96px); }

.section--paper { background-color: var(--c-paper); color: var(--c-text); }
.section--dark { background-color: var(--c-ink); color: var(--c-paper); }
.section--night { background-color: var(--c-night); color: var(--c-paper); }

.section-head {
  max-width: 70ch;
  margin-bottom: clamp(24px, 3.2vw, 40px);
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.20em;
  color: var(--c-orange-deep);
  margin-bottom: 12px;
}

.section--dark .eyebrow,
.section--night .eyebrow,
.panel .eyebrow { color: var(--c-gold); }

.section-title {
  font-size: clamp(26px, 3.5vw, 34px);
  margin-bottom: 14px;
}

.section-lead {
  font-size: 17px;
  line-height: 1.8;
  color: var(--c-muted);
  max-width: 64ch;
}

.section--dark .section-lead,
.section--night .section-lead { color: rgba(244, 241, 232, 0.70); }

.rule-gold {
  display: block;
  width: 64px;
  height: 2px;
  border: 0;
  background: var(--c-gold);
  margin-bottom: 20px;
}

.divider {
  height: 1px;
  border: 0;
  background: var(--c-line);
  margin-block: clamp(28px, 4vw, 56px);
}

.divider--dark { background: var(--c-line-dark); }

/* 非对称主栏 + 旁栏 */
.layout-split {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
  gap: clamp(24px, 4vw, 56px);
  align-items: start;
}

.grid-2,
.grid-3,
.grid-4 {
  display: grid;
  gap: clamp(18px, 2.2vw, 26px);
}

.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)); }

/* ==========================================================================
   文本块
   ========================================================================== */
.prose {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.8;
  color: var(--c-text);
  overflow-wrap: break-word;
}

.prose > * + * { margin-top: 1.05em; }

.prose h2 {
  font-size: clamp(23px, 2.8vw, 30px);
  margin-top: 1.9em;
}

.prose h3 {
  font-size: 20px;
  margin-top: 1.6em;
}

.prose a {
  color: var(--c-orange-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.prose a:hover { color: var(--c-brick); }

.prose ul,
.prose ol {
  padding-left: 1.35em;
  list-style: disc;
}

.prose ol { list-style: decimal; }
.prose li + li { margin-top: 0.5em; }

.prose blockquote {
  padding: 4px 0 4px 18px;
  border-left: 2px solid var(--c-gold);
  color: var(--c-muted);
}

/* ==========================================================================
   面包屑
   ========================================================================== */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--c-muted);
  padding-block: 18px;
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.breadcrumb li + li::before {
  content: "/";
  margin-right: 8px;
  color: rgba(91, 100, 114, 0.55);
}

.breadcrumb a {
  color: var(--c-muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.breadcrumb a:hover {
  color: var(--c-orange-deep);
  border-bottom-color: currentColor;
}

.section--dark .breadcrumb,
.section--night .breadcrumb { color: rgba(244, 241, 232, 0.62); }

.section--dark .breadcrumb a,
.section--night .breadcrumb a { color: rgba(244, 241, 232, 0.62); }

/* ==========================================================================
   按钮
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  font-family: var(--font-ui);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1;
  border: 1px solid transparent;
  border-radius: var(--radius);
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.16s var(--ease), color 0.16s var(--ease),
              border-color 0.16s var(--ease), transform 0.16s var(--ease);
}

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

.btn--gold {
  background-color: var(--c-gold);
  border-color: var(--c-gold);
  color: var(--c-ink);
}

.btn--gold:hover {
  background-color: var(--c-gold-soft);
  border-color: var(--c-gold-soft);
}

.btn--orange {
  background-color: var(--c-orange);
  border-color: var(--c-orange);
  color: #FFFFFF;
}

.btn--orange:hover {
  background-color: var(--c-orange-deep);
  border-color: var(--c-orange-deep);
}

.btn--outline {
  background-color: transparent;
  border-color: rgba(244, 241, 232, 0.42);
  color: var(--c-paper);
}

.btn--outline:hover {
  border-color: var(--c-gold);
  color: var(--c-gold);
}

.btn--ink {
  background-color: transparent;
  border-color: var(--c-line-strong);
  color: var(--c-text);
}

.btn--ink:hover {
  border-color: var(--c-orange);
  color: var(--c-orange-deep);
}

.btn[disabled],
.btn[aria-disabled="true"] {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

/* ==========================================================================
   卡片 / 面板 / 标签 / 色带
   ========================================================================== */
.card {
  background-color: var(--c-white);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: clamp(18px, 2.4vw, 26px);
  box-shadow: var(--shadow-1);
  transition: transform 0.14s var(--ease), border-color 0.14s var(--ease), box-shadow 0.14s var(--ease);
}

.card:hover {
  transform: translateY(-2px);
  border-color: rgba(232, 178, 58, 0.72);
}

.panel {
  background-color: var(--c-night);
  border: 1px solid var(--c-line-dark);
  border-radius: var(--radius);
  padding: clamp(20px, 2.6vw, 30px);
  color: var(--c-paper);
  transition: transform 0.14s var(--ease), border-color 0.14s var(--ease);
}

.panel:hover { border-color: rgba(232, 178, 58, 0.6); }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  line-height: 1.6;
  color: var(--c-muted);
  background-color: var(--c-white);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
}

.tag--gold {
  color: var(--c-orange-deep);
  background-color: rgba(247, 227, 176, 0.42);
  border-color: rgba(232, 178, 58, 0.62);
}

.tag--grass {
  color: #1F6A41;
  background-color: rgba(47, 143, 91, 0.10);
  border-color: rgba(47, 143, 91, 0.48);
}

.league-band {
  display: block;
  width: 100%;
  height: 4px;
  background-color: var(--c-moss);
}

.league-band--l1 { background-color: var(--c-grass); }
.league-band--l2 { background-color: var(--c-gold); }
.league-band--l3 { background-color: var(--c-orange); }
.league-band--l4 { background-color: var(--c-brick); }
.league-band--short { width: 48px; }

/* ==========================================================================
   数字与指标
   ========================================================================== */
.stat { display: block; }

.stat-value {
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(32px, 5vw, 64px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--c-gold);
}

.stat-value--ink { color: var(--c-text); }
.stat-value--orange { color: var(--c-orange-deep); }
.stat-value--grass { color: var(--c-grass); }

.stat-label {
  display: block;
  margin-top: 10px;
  font-family: var(--font-ui);
  font-size: 13px;
  letter-spacing: 0.10em;
  color: var(--c-muted);
}

.section--dark .stat-label,
.section--night .stat-label,
.panel .stat-label { color: rgba(244, 241, 232, 0.64); }

/* ==========================================================================
   图片容器（页面阶段放置 <img> 即可自适应）
   ========================================================================== */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background-color: var(--c-night);
  background-image:
    linear-gradient(rgba(244, 241, 232, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(244, 241, 232, 0.055) 1px, transparent 1px);
  background-size: 32px 32px, 32px 32px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
}

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

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

.media-frame__caption {
  position: absolute;
  inset: auto 0 0 0;
  padding: 14px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: rgba(244, 241, 232, 0.88);
  background-image: linear-gradient(transparent, rgba(12, 26, 46, 0.86));
}

/* ==========================================================================
   数据表
   ========================================================================== */
.table-wrap {
  overflow-x: auto;
  background-color: var(--c-white);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
}

.data-table {
  width: 100%;
  font-size: 15px;
  line-height: 1.6;
}

.data-table thead th {
  background-color: var(--c-night);
  color: var(--c-paper);
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: 12px 16px;
  white-space: nowrap;
}

.data-table td {
  padding: 12px 16px;
  border-top: 1px solid var(--c-line);
  vertical-align: top;
}

.data-table tbody tr:nth-child(even) { background-color: var(--c-paper); }

.data-table .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

/* ==========================================================================
   粘性索引目录
   ========================================================================== */
.toc {
  position: sticky;
  top: 24px;
  align-self: start;
}

.toc-title {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--c-muted);
  margin-bottom: 12px;
}

.toc a {
  display: block;
  padding: 9px 0 9px 14px;
  border-left: 2px solid var(--c-line);
  font-size: 14px;
  line-height: 1.5;
  color: var(--c-muted);
  text-decoration: none;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.toc a:hover {
  color: var(--c-text);
  border-left-color: var(--c-gold);
}

.toc a[aria-current="location"] {
  color: var(--c-orange-deep);
  border-left-color: var(--c-orange);
  font-weight: 700;
}

/* ==========================================================================
   可展开内容组 / 纯前端筛选
   ========================================================================== */
.disclosure {
  border-top: 1px solid var(--c-line);
}

.disclosure:last-of-type { border-bottom: 1px solid var(--c-line); }

.disclosure > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-ui);
  font-size: 17px;
  font-weight: 700;
  color: var(--c-text);
}

.disclosure > summary::-webkit-details-marker { display: none; }

.disclosure > summary::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 20px;
  line-height: 1;
  color: var(--c-orange-deep);
  transition: transform 0.18s var(--ease);
}

.disclosure[open] > summary::after { transform: rotate(45deg); }

.disclosure__body {
  padding: 0 0 20px;
  font-size: 16px;
  line-height: 1.8;
  color: var(--c-muted);
}

.disclosure__body > * + * { margin-top: 0.9em; }

.filter-set {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.filter-chip {
  position: relative;
  display: inline-flex;
}

.filter-chip input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.filter-chip > span {
  display: inline-block;
  padding: 8px 15px;
  font-family: var(--font-ui);
  font-size: 14px;
  font-weight: 600;
  color: var(--c-muted);
  background-color: var(--c-white);
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  cursor: pointer;
  transition: background-color 0.16s var(--ease), color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.filter-chip:hover > span {
  border-color: rgba(232, 178, 58, 0.72);
  color: var(--c-text);
}

.filter-chip input:checked + span {
  background-color: var(--c-ink);
  border-color: var(--c-ink);
  color: var(--c-gold);
}

.filter-chip input:focus-visible + span {
  outline: 2px solid var(--c-gold);
  outline-offset: 2px;
}

/* ==========================================================================
   进入动画（脚本加 .js-on 后才启用初始隐藏，避免无 JS 时不可见）
   ========================================================================== */
.js-on [data-reveal] {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.2s var(--ease), transform 0.2s var(--ease);
}

.js-on [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1080px) {
  .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 900px) {
  .layout-split { grid-template-columns: minmax(0, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-inner { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: 1 / -1; }
  .toc { position: static; }
}

@media (max-width: 880px) {
  .nav-toggle { display: inline-flex; }

  .site-nav {
    display: none;
    align-items: stretch;
    width: 100%;
    margin-top: 16px;
    padding: 4px 0 14px;
    border-top: 1px solid var(--c-line-dark);
  }

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

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-link {
    padding: 13px 14px;
    text-align: left;
    border-bottom: 0;
    border-left: 2px solid transparent;
    font-size: 16px;
  }

  .nav-link:hover { border-left-color: rgba(232, 178, 58, 0.5); border-bottom-color: transparent; }
  .nav-link[aria-current="page"] { border-left-color: var(--c-gold); border-bottom-color: transparent; }

  .index-list {
    flex-direction: column;
    align-items: stretch;
    margin-top: 10px;
  }

  .index-list a {
    padding: 9px 14px;
    border-right: 0;
    border-bottom: 1px solid var(--c-line-dark-soft);
  }

  .index-list li:last-child a { border-bottom: 0; }

  .nav-cta {
    margin-top: 18px;
    padding-inline: 14px;
  }

  .nav-cta .btn { width: 100%; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }

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

  .footer-inner { grid-template-columns: minmax(0, 1fr); }
  .footer-brand { grid-column: auto; }

  .header-rule { margin-top: 18px; }
}

/* ==========================================================================
   减弱动效
   ========================================================================== */
@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;
  }

  .js-on [data-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }

  .card:hover,
  .panel:hover,
  .btn:active { transform: none; }
}