/* ============================================================
   中欧赛场 · 共享样式表 /assets/site.css
   午夜赛场 · 数据流 —— 深翡翠底、熔金编号、霓虹青升级态
   ============================================================ */

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

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

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

ul, ol { list-style: none; }
img, svg, video { display: block; max-width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
a { color: inherit; text-decoration: none; }
[hidden] { display: none !important; }
table { border-collapse: collapse; width: 100%; }

/* ---------- 2. 变量 ---------- */
:root {
  --c-emerald-lit: #0F4A3D;
  --c-emerald: #0B3B32;
  --c-emerald-deep: #062A24;
  --c-charcoal: #101512;
  --c-paper: #143229;
  --c-gold: #C9A227;
  --c-gold-lit: #E4C56B;
  --c-silver: #C8D3D1;
  --c-cyan: #4FE3D0;
  --c-amber: #E8B44A;
  --c-ink: #F2F7F4;

  --line-gold: rgba(201, 162, 39, .34);
  --line-hair: rgba(200, 211, 209, .16);
  --glow-cyan: 0 0 0 1px rgba(79, 227, 208, .32), 0 0 26px rgba(79, 227, 208, .16);
  --shadow-sheet: 0 20px 44px -26px rgba(0, 0, 0, .8);

  --wrap: 1180px;
  --gutter: clamp(20px, 5vw, 48px);

  --font-head: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Heiti SC", sans-serif;
  --font-body: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "SimSun", "Source Han Serif", serif;
  --font-mono: ui-monospace, "SFMono-Regular", "Cascadia Mono", Consolas, "Noto Sans Mono", "Courier New", monospace;
}

/* ---------- 3. 基础排版与背景分区 ---------- */
body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-weight: 300;
  font-size: clamp(16px, 0.42vw + 15px, 18px);
  line-height: 1.9;
  letter-spacing: .01em;
  color: var(--c-ink);
  background-color: var(--c-emerald-deep);
  background-image: linear-gradient(180deg, #0F4A3D 0%, #0B3B32 40%, #062A24 74%, #101512 100%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(90deg, rgba(200, 211, 209, .05) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(79, 227, 208, .03) 0 1px, transparent 1px 140px);
}

@supports (background-attachment: fixed) {
  @media (min-width: 901px) {
    body { background-attachment: fixed; }
  }
}

main,
.site-footer { position: relative; z-index: 1; }

#main-content { scroll-margin-top: 132px; }

h1, h2, h3, h4 {
  font-family: var(--font-head);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -.01em;
}

h1 { font-size: clamp(34px, 5.4vw, 62px); }
h2 { font-size: clamp(26px, 3.4vw, 40px); }
h3 { font-size: clamp(20px, 2.2vw, 26px); }

p + p { margin-top: 1em; }

::selection { background: rgba(79, 227, 208, .35); color: #04120F; }

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

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

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .26em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.lede {
  max-width: 62ch;
  font-size: clamp(17px, 1.1vw + 14px, 20px);
  line-height: 1.95;
  color: rgba(242, 247, 244, .9);
}

.vertical-note {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-head);
  font-weight: 500;
  font-size: 13px;
  letter-spacing: .3em;
  color: rgba(200, 211, 209, .55);
  white-space: nowrap;
}

/* ---------- 5. 布局基座 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  position: relative;
  padding-block: clamp(56px, 9vw, 112px);
}

.section--tight { padding-block: clamp(32px, 5vw, 62px); }

.band {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, transparent 0%, var(--line-gold) 18%, var(--c-gold) 50%, var(--line-gold) 82%, transparent 100%);
}

.section-head {
  display: grid;
  grid-template-columns: minmax(88px, 148px) minmax(0, 1fr);
  gap: clamp(16px, 3vw, 42px);
  align-items: start;
}

.chapter-num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(56px, 10vw, 120px);
  line-height: .84;
  letter-spacing: -.03em;
  background: linear-gradient(160deg, var(--c-gold-lit), var(--c-gold) 55%, rgba(201, 162, 39, .35));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.grid { display: grid; gap: clamp(20px, 3vw, 32px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 1.35fr) minmax(260px, .65fr); }

/* ---------- 6. 通用组件 ---------- */
.sheet {
  position: relative;
  z-index: 0;
  background: linear-gradient(160deg, rgba(20, 50, 41, .96), rgba(11, 59, 50, .84));
  border: 1px solid var(--line-hair);
  box-shadow: var(--shadow-sheet);
  padding: clamp(20px, 3vw, 34px);
}

.sheet--stack::before,
.sheet--stack::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  border: 1px solid var(--line-hair);
  background: rgba(20, 50, 41, .5);
}

.sheet--stack::before { transform: translate(8px, 8px); }
.sheet--stack::after { transform: translate(16px, 16px); opacity: .5; }

.print-border { position: relative; border: 1px solid var(--line-gold); }

.print-border::after {
  content: "";
  position: absolute;
  inset: 6px;
  border: 1px dashed rgba(201, 162, 39, .3);
  pointer-events: none;
}

.label-tag {
  display: inline-flex;
  align-items: center;
  gap: .55em;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--c-ink);
  background: var(--c-emerald-lit);
  border: 1px solid var(--line-gold);
  padding: 4px 11px;
}

.label-tag::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--c-gold);
  transform: rotate(45deg);
}

.label-tag--cyan {
  border-color: rgba(79, 227, 208, .5);
  color: var(--c-cyan);
  background: rgba(79, 227, 208, .08);
}
.label-tag--cyan::before { background: var(--c-cyan); }

.label-tag--amber {
  border-color: rgba(232, 180, 74, .5);
  color: var(--c-amber);
  background: rgba(232, 180, 74, .08);
}
.label-tag--amber::before { background: var(--c-amber); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: .6em;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .06em;
  padding: 12px 26px;
  border: 1px solid var(--line-gold);
  color: var(--c-ink);
  background: linear-gradient(120deg, rgba(201, 162, 39, .18), rgba(201, 162, 39, .02));
  transition: transform .2s ease, background .2s ease, border-color .2s ease, color .2s ease;
}

.btn:hover {
  transform: translateY(-2px);
  border-color: var(--c-gold-lit);
  background: linear-gradient(120deg, rgba(228, 197, 107, .3), rgba(201, 162, 39, .06));
}

.btn--gold {
  color: #171307;
  border-color: transparent;
  background: linear-gradient(120deg, var(--c-gold), var(--c-gold-lit));
}
.btn--gold:hover { background: linear-gradient(120deg, var(--c-gold-lit), #F3E1A6); }

.btn--cyan {
  color: var(--c-cyan);
  border-color: rgba(79, 227, 208, .5);
  background: rgba(79, 227, 208, .1);
  box-shadow: var(--glow-cyan);
}
.btn--cyan:hover { background: rgba(79, 227, 208, .2); }

.btn--ghost {
  background: transparent;
  border-style: dashed;
  color: var(--c-silver);
}
.btn--ghost:hover { color: var(--c-ink); }

.crumbs { margin-block: 18px 0; }

.crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .08em;
  color: var(--c-silver);
}

.crumbs li { display: inline-flex; align-items: center; }
.crumbs li + li::before { content: "／"; margin-inline: .5em; color: var(--line-gold); }
.crumbs a:hover { color: var(--c-gold-lit); }
.crumbs [aria-current="page"] { color: var(--c-gold-lit); }

.glance-panel {
  position: relative;
  background: linear-gradient(180deg, rgba(15, 74, 61, .86), rgba(6, 42, 36, .92));
  border: 1px solid rgba(79, 227, 208, .3);
  box-shadow: var(--glow-cyan);
  padding: 20px;
}

.glance-panel__title {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--c-cyan);
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-hair);
}

.glance-list li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line-hair);
  font-size: 15px;
  line-height: 1.6;
}
.glance-list li:last-child { border-bottom: 0; }
.glance-list .mono { color: var(--c-gold-lit); }

.stat-block {
  display: grid;
  gap: 4px;
  padding: 16px 18px;
  border: 1px solid var(--line-hair);
  background: rgba(20, 50, 41, .68);
}
.stat-block__num {
  font-family: var(--font-mono);
  font-size: clamp(22px, 2.4vw, 30px);
  line-height: 1.2;
  color: var(--c-gold-lit);
}
.stat-block__label { font-size: 13px; color: var(--c-silver); }

/* 图片容器基础规则（供页面阶段放置图片） */
.figure { margin: 0; }

.figure__frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--line-hair);
  background:
    linear-gradient(140deg, #0F4A3D 0%, #0B3B32 45%, #101512 100%);
}

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

.figure__frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(0deg, rgba(242, 247, 244, .06) 0 1px, transparent 1px 3px);
  mix-blend-mode: overlay;
}

.figure__frame--tall { aspect-ratio: 4 / 5; }
.figure__frame--wide { aspect-ratio: 21 / 9; }
.figure__frame--square { aspect-ratio: 1 / 1; }

.figure__cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--c-silver);
}

/* 旧版资讯区：颗粒 + 暖黄怀旧滤镜 */
.grain,
.legacy-zone { position: relative; }

.grain::before,
.legacy-zone::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: .06;
  background-image:
    repeating-linear-gradient(45deg, #E8B44A 0 1px, transparent 1px 4px),
    repeating-linear-gradient(-30deg, #E8B44A 0 1px, transparent 1px 6px);
}

.legacy-zone {
  background: linear-gradient(180deg, rgba(16, 21, 18, .92), rgba(11, 59, 50, .72));
  border-top: 1px solid rgba(232, 180, 74, .3);
  border-bottom: 1px solid rgba(232, 180, 74, .3);
}

.legacy-zone .figure__frame { filter: sepia(.18) saturate(.94); }

/* 主题筛选条 */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  padding-block: 6px 22px;
}

.filter-chip {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .12em;
  padding: 8px 15px;
  color: var(--c-silver);
  background: rgba(20, 50, 41, .62);
  border: 1px solid var(--line-hair);
  transition: color .16s ease, border-color .16s ease, background .16s ease;
}

.filter-chip:hover { color: var(--c-ink); border-color: var(--c-gold-lit); }

.filter-chip[aria-pressed="true"] {
  color: var(--c-cyan);
  border-color: rgba(79, 227, 208, .55);
  background: rgba(79, 227, 208, .1);
  box-shadow: var(--glow-cyan);
}

.filter-status {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--c-silver);
  margin-left: auto;
}

@keyframes filterIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

.filter-pop { animation: filterIn .16s ease-out; }

/* 滚动显现 */
[data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .7s ease-out, transform .7s cubic-bezier(.2, .7, .3, 1);
  transition-delay: var(--reveal-delay, 0ms);
  will-change: opacity, transform;
}

[data-reveal].is-in { opacity: 1; transform: none; }

/* ---------- 7. 头部 ---------- */
.skip-link {
  position: absolute;
  left: 50%;
  top: -80px;
  transform: translateX(-50%);
  z-index: 200;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 14px;
  padding: 10px 22px;
  color: #171307;
  background: var(--c-gold-lit);
  transition: top .2s ease;
}

.skip-link:focus { top: 8px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: linear-gradient(180deg, rgba(6, 42, 36, .97), rgba(6, 42, 36, .88));
  border-bottom: 1px solid var(--line-gold);
  backdrop-filter: blur(10px);
}

.site-header::after {
  content: "";
  display: block;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(79, 227, 208, .45) 25%, rgba(201, 162, 39, .75) 50%, rgba(79, 227, 208, .45) 75%, transparent);
}

.header-inner {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 14px var(--gutter) 0;
  display: grid;
  gap: 6px;
}

.header-top {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
}

.masthead {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(14px, 3vw, 40px);
  padding-inline: 58px;
  text-align: center;
}

.masthead__brand { display: grid; gap: 3px; }

.masthead__kicker {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .42em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.masthead__name {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(26px, 3.4vw, 44px);
  line-height: 1.06;
  letter-spacing: .16em;
  color: var(--c-ink);
  text-shadow: 0 0 28px rgba(79, 227, 208, .22);
  transition: color .2s ease, font-size .24s ease;
}

.masthead__brand:hover .masthead__name { color: var(--c-gold-lit); }

.masthead__domain {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .28em;
  color: var(--c-silver);
  opacity: .72;
}

.masthead__note { color: rgba(200, 211, 209, .5); }

.nav-toggle {
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  display: grid;
  justify-items: center;
  gap: 6px;
  padding: 10px 12px;
  border: 1px solid var(--line-gold);
  background: rgba(20, 50, 41, .6);
  color: var(--c-silver);
}

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 20px;
  height: 2px;
  background: var(--c-silver);
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 20px;
  height: 2px;
  background: var(--c-silver);
  transition: transform .22s ease;
}

.nav-toggle__bars::before { top: -6px; }
.nav-toggle__bars::after { top: 6px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-6px) rotate(-45deg); }

.nav-toggle__text {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
}

.header-actions {
  display: none;
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  align-items: center;
  gap: 10px;
}

.link-chip {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  color: var(--c-silver);
  padding: 7px 13px;
  border: 1px solid var(--line-hair);
  background: rgba(20, 50, 41, .55);
  transition: color .18s ease, border-color .18s ease;
}

.link-chip:hover { color: var(--c-cyan); border-color: rgba(79, 227, 208, .5); }

.site-nav {
  border-top: 1px solid var(--line-hair);
  padding-block: 4px;
}

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: clamp(8px, 2.4vw, 30px);
}

.site-nav__link {
  position: relative;
  display: inline-block;
  padding: 11px 4px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: .08em;
  color: var(--c-silver);
  transition: color .2s ease, font-size .24s ease;
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 4px;
  width: 0;
  height: 1px;
  transform: translateX(-50%);
  background: var(--c-gold-lit);
  transition: width .24s ease;
}

.site-nav__link:hover { color: var(--c-ink); }
.site-nav__link:hover::after { width: 100%; }

.site-nav__link[aria-current="page"] { color: var(--c-gold-lit); }

.site-nav__link[aria-current="page"]::after {
  width: 100%;
  background: var(--c-gold-lit);
  box-shadow: 0 0 12px rgba(228, 197, 107, .65);
}

/* 滚动收起态：窄条 + 三个高频入口 */
.site-header[data-stuck] .header-inner { padding-top: 6px; }
.site-header[data-stuck] .masthead__kicker,
.site-header[data-stuck] .masthead__domain,
.site-header[data-stuck] .masthead__note { display: none; }
.site-header[data-stuck] .masthead__brand { gap: 0; }

/* ---------- 8. 左侧赛道标线导航轨 ---------- */
.track-rail { display: none; }

/* ---------- 9. 移动端底部快捷条 ---------- */
.quick-bar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 70;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line-gold);
  background: linear-gradient(180deg, rgba(6, 42, 36, .95), rgba(11, 59, 50, .99));
  backdrop-filter: blur(10px);
  padding-block: 7px;
}

.quick-bar__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: 6px 2px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--c-silver);
}

.quick-bar__glyph { font-size: 11px; color: var(--c-gold); }
.quick-bar__item:hover,
.quick-bar__item[aria-current="page"] { color: var(--c-cyan); }

/* ---------- 10. 页脚 ---------- */
.site-footer {
  margin-top: clamp(48px, 8vw, 96px);
  padding-block: clamp(44px, 7vw, 82px) 26px;
  border-top: 1px solid var(--line-gold);
  background: linear-gradient(180deg, #062A24 0%, #101512 100%);
}

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

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.35fr;
  gap: clamp(24px, 4vw, 52px);
}

.footer-brand { display: grid; gap: 6px; margin-bottom: 14px; }

.footer-brand__name {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: 26px;
  letter-spacing: .16em;
  color: var(--c-ink);
}

.footer-brand__domain {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .24em;
  color: var(--c-silver);
  opacity: .7;
}

.footer-line {
  max-width: 34ch;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--c-silver);
}

.footer-line--muted { margin-top: 10px; font-size: 13px; opacity: .62; }

.footer-title {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 12px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--c-gold);
  margin-bottom: 16px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--line-hair);
}

.footer-list { display: grid; gap: 10px; }

.footer-list a {
  font-size: 15px;
  color: var(--c-silver);
  transition: color .18s ease, padding-left .18s ease;
}

.footer-list a:hover { color: var(--c-gold-lit); padding-left: 5px; }

.footer-list--contact { font-size: 14.5px; color: var(--c-silver); }
.footer-list--contact li { display: grid; gap: 2px; line-height: 1.7; }

.footer-key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--c-cyan);
  opacity: .85;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-top: clamp(32px, 5vw, 58px);
  padding-top: 18px;
  border-top: 1px solid var(--line-hair);
}

.footer-copy {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--c-silver);
  opacity: .8;
}

.to-top {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 13px;
  letter-spacing: .1em;
  padding: 9px 18px;
  color: var(--c-ink);
  border: 1px solid var(--line-gold);
  background: rgba(201, 162, 39, .1);
  transition: background .2s ease, color .2s ease, transform .2s ease;
}

.to-top:hover { background: var(--c-gold); color: #171307; transform: translateY(-2px); }

/* ---------- 11. 平板 ---------- */
@media (max-width: 1024px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 1000px) {
  .masthead__note { display: none; }
}

/* ---------- 12. 手机 ---------- */
@media (max-width: 900px) {
  body { padding-bottom: 74px; }

  .header-inner { padding-top: 10px; }
  .header-top { min-height: 46px; }
  .masthead { padding-inline: 54px; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    padding: 8px var(--gutter) 18px;
    border-top: 1px solid var(--line-gold);
    border-bottom: 1px solid var(--line-gold);
    background: linear-gradient(180deg, #0B3B32 0%, #062A24 100%);
  }

  .js .site-nav {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    visibility: hidden;
    transition: max-height .34s ease, opacity .24s ease, visibility .24s;
  }

  .js .site-nav[data-open] {
    max-height: min(72vh, 540px);
    overflow-y: auto;
    opacity: 1;
    visibility: visible;
  }

  html:not(.js) .nav-toggle { display: none; }

  .site-nav__list { flex-direction: column; align-items: stretch; gap: 0; }

  .site-nav__link {
    display: block;
    padding: 15px 0;
    font-size: 17px;
    border-bottom: 1px dashed var(--line-hair);
  }

  .site-nav__link::after { display: none; }
  .site-nav__link[aria-current="page"] { color: var(--c-cyan); }

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

  .section-head { grid-template-columns: minmax(0, 1fr); gap: 10px; }
  .chapter-num { font-size: clamp(52px, 17vw, 88px); }

  .filter-status { margin-left: 0; width: 100%; }
}

@media (max-width: 600px) {
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-bottom { align-items: flex-start; }
}

/* ---------- 13. 桌面：悬浮赛道轨 + 收起态高频入口 ---------- */
@media (min-width: 901px) {
  .nav-toggle { display: none; }
}

@media (min-width: 1025px) {
  .site-header[data-stuck] .header-actions { display: flex; }
  .site-header[data-stuck] .masthead__name { font-size: clamp(20px, 2vw, 28px); }
  .site-header[data-stuck] .site-nav { padding-block: 0; }
  .site-header[data-stuck] .site-nav__link { font-size: 14px; padding-block: 8px; }
}

@media (min-width: 1100px) {
  .track-rail {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 18px;
    position: fixed;
    left: clamp(12px, 1.6vw, 26px);
    top: 50%;
    transform: translateY(-50%);
    z-index: 55;
    padding: 18px 10px;
    border: 1px solid var(--line-hair);
    background: rgba(6, 42, 36, .62);
    backdrop-filter: blur(6px);
  }

  .track-rail__mark {
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: .4em;
    color: rgba(200, 211, 209, .55);
  }

  .track-rail__line {
    position: relative;
    display: block;
    width: 2px;
    height: 108px;
    background: rgba(200, 211, 209, .18);
    overflow: hidden;
  }

  .track-rail__fill {
    position: absolute;
    inset: 0;
    transform: scaleY(0);
    transform-origin: top center;
    background: linear-gradient(180deg, var(--c-cyan), var(--c-gold));
  }

  .track-rail__list {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
  }

  .track-rail__list a {
    writing-mode: vertical-rl;
    font-family: var(--font-head);
    font-weight: 700;
    font-size: 12.5px;
    letter-spacing: .24em;
    padding: 4px;
    color: var(--c-silver);
    transition: color .18s ease;
  }

  .track-rail__list a:hover { color: var(--c-cyan); }
}

@media (min-width: 901px) {
  .quick-bar { display: none; }
}

/* ---------- 14. 降低动态效果 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  [data-reveal] { opacity: 1; transform: none; }
  .filter-pop { animation: none; }
}