/* ==========================================================================
   聚合入口 · 共享外壳样式  /assets/site.css
   纵向叙事长卷 / 左右分置导航 / 珠宝色分区 / 粗野主义边框
   ========================================================================== */

/* ---------- 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, blockquote, dl, dt, dd, table, th, td { margin: 0; padding: 0; }
ul, ol { list-style: none; }
table { border-collapse: collapse; width: 100%; }
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; }

/* ---------- 2. 变量 ---------- */
:root {
  --ink-900: #0B1030;
  --ink-800: #171C4A;
  --band-teal: #0E3B3E;
  --band-wine: #4A1633;
  --cyan: #35E6D0;
  --gold: #F2B441;
  --coral: #FF6B5A;
  --paper: #EEF1F8;
  --slate: #2A3050;
  --index: #8A93B8;
  --edge: #2C3370;
  --edge-soft: #232A5C;
  --text-dark: #D9DDF2;
  --text-mute: #A8B0D4;

  --font-display: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans SC", system-ui, sans-serif;
  --font-body: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", "Courier New", monospace;

  --bw: 2px;
  --shadow-hard: 6px 6px 0 #05071A;
  --shadow-hard-cyan: 5px 5px 0 rgba(53, 230, 208, 0.28);
  --shell-max: 1240px;
  --gutter: clamp(18px, 4vw, 40px);
  --section-y: clamp(48px, 7vw, 104px);
}

/* ---------- 3. 基础排版 ---------- */
body {
  background: var(--ink-900);
  color: var(--text-dark);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  min-height: 100%;
  overflow-x: hidden;
}
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--paper);
}
h1 { font-size: clamp(28px, 4.4vw, 40px); }
h2 { font-size: clamp(22px, 3vw, 28px); }
h3 { font-size: clamp(18px, 2.2vw, 22px); }
p { max-width: 74ch; }
::selection { background: var(--cyan); color: var(--ink-900); }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; }
body[data-nav-open] { overflow: hidden; }
#main-content { display: block; scroll-margin-top: 104px; }

.shell {
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.mono {
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
  font-variant-numeric: tabular-nums;
}

/* ---------- 4. skip link ---------- */
.skip-link {
  position: fixed;
  left: 12px;
  top: -72px;
  z-index: 200;
  background: var(--gold);
  color: var(--ink-900);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  padding: 10px 18px;
  border: var(--bw) solid var(--ink-900);
  transition: top 0.16s ease;
}
.skip-link:focus { top: 12px; }

/* ---------- 5. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: var(--ink-900);
  border-bottom: var(--bw) solid var(--edge-soft);
}
.header-inner {
  display: flex;
  align-items: center;
  gap: clamp(14px, 3vw, 44px);
  min-height: 82px;
}
.brand-cluster {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 21px;
  letter-spacing: -0.02em;
  color: var(--paper);
}
.brand-mark {
  flex: none;
  width: 12px;
  height: 12px;
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(53, 230, 208, 0.18);
  animation: nodePulse 1.6s ease-in-out infinite;
}
.brand:hover .brand-mark { background: var(--gold); box-shadow: 0 0 0 3px rgba(242, 180, 65, 0.24); }
.brand-name { white-space: nowrap; }
.brand-status {
  display: flex;
  align-items: center;
  gap: 7px;
  max-width: 100%;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.4;
  letter-spacing: 0.08em;
  color: var(--index);
  white-space: nowrap;
}
.status-dot {
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--cyan);
  animation: nodePulse 1.6s ease-in-out infinite;
}
.status-text { overflow: hidden; text-overflow: ellipsis; }
.mono-num { font-family: var(--font-mono); color: var(--cyan); font-weight: 700; }

@keyframes nodePulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  margin-left: auto;
  padding: 9px 14px;
  background: var(--ink-800);
  border: var(--bw) solid var(--edge);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
}
.nav-toggle:hover { border-color: var(--cyan); color: var(--cyan); }
.nav-toggle-bars {
  position: relative;
  flex: none;
  width: 16px;
  height: 2px;
  background: currentColor;
}
.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background: currentColor;
  transition: transform 0.2s 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 { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after { transform: translateY(-5px) rotate(-45deg); }
.nav-toggle-label { white-space: nowrap; }

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(10px, 1.8vw, 26px);
  margin-left: auto;
}
.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.5vw, 22px);
}
.nav-item { display: block; }
.nav-link {
  position: relative;
  display: inline-block;
  padding: 10px 2px;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  color: #C3C9E8;
  transition: color 0.18s ease;
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 3px;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.22s ease;
}
.nav-link:hover,
.nav-link:focus-visible { color: var(--paper); }
.nav-link:hover::after,
.nav-link:focus-visible::after { transform: scaleX(1); }
.nav-link[aria-current="page"] { color: var(--gold); }
.nav-link[aria-current="page"]::after { background: var(--gold); transform: scaleX(1); }

.nav-extra { display: none; }
.nav-sub {
  font-size: 13px;
  color: var(--index);
  padding-bottom: 2px;
  border-bottom: 1px solid var(--edge);
}
.nav-sub:hover { color: var(--cyan); border-color: var(--cyan); }

.nav-cta {
  padding: 10px 18px;
  font-size: 14px;
  box-shadow: 4px 4px 0 #05071A;
  white-space: nowrap;
}

.header-rule {
  height: 4px;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--band-teal) 24%, var(--band-wine) 58%, var(--edge-soft) 100%);
  opacity: 0.9;
}
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  background: var(--gold);
  transform: scaleX(0);
  transform-origin: left;
  z-index: 5;
}

/* ---------- 6. 页脚 ---------- */
.site-footer {
  margin-top: clamp(56px, 8vw, 120px);
  background: var(--ink-800);
  border-top: var(--bw) solid var(--band-teal);
  color: #C3C9E8;
}
.footer-grid {
  display: grid;
  grid-template-columns: 5fr 4fr 3fr;
  gap: clamp(24px, 4vw, 56px);
  padding-block: clamp(40px, 6vw, 72px);
}
.footer-col { min-width: 0; }
.footer-title {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--index);
  margin-bottom: 14px;
  text-transform: uppercase;
}
.footer-brand-name {
  display: inline-block;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 26px;
  letter-spacing: -0.02em;
  color: var(--paper);
}
.footer-brand-name:hover { color: var(--cyan); }
.footer-promise {
  margin-top: 10px;
  font-size: 15px;
  color: #C3C9E8;
}
.footer-icp {
  margin-top: 18px;
  padding-left: 10px;
  border-left: 3px solid var(--gold);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--index);
}

.path-list { counter-reset: pathstep; }
.path-step {
  counter-increment: pathstep;
  position: relative;
  margin-left: 6px;
  padding: 9px 0 9px 34px;
  border-left: 1px solid rgba(53, 230, 208, 0.25);
  font-size: 15px;
}
.path-step:last-child { border-left-color: transparent; }
.path-step::before {
  content: counter(pathstep, decimal-leading-zero);
  position: absolute;
  left: -8px;
  top: 11px;
  padding: 1px 5px;
  background: var(--cyan);
  color: var(--ink-900);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.5;
  letter-spacing: 0.04em;
}
.path-step a { color: #C3C9E8; }
.path-step a:hover { color: var(--gold); }

.contact-list { display: flex; flex-direction: column; gap: 14px; }
.contact-item { display: flex; flex-direction: column; gap: 2px; }
.contact-key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--index);
  text-transform: uppercase;
}
.contact-value {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--paper);
  word-break: break-word;
}
.contact-note {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px solid var(--edge);
  font-size: 13px;
  line-height: 1.7;
  color: var(--index);
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-block: 18px 28px;
  border-top: 1px solid var(--edge);
}
.footer-legal { font-size: 13px; color: var(--index); }
.footer-legal a {
  color: #C3C9E8;
  border-bottom: 1px solid var(--edge);
}
.footer-legal a:hover { color: var(--cyan); border-color: var(--cyan); }

.to-top {
  position: fixed;
  right: clamp(14px, 3vw, 28px);
  bottom: clamp(14px, 3vw, 28px);
  z-index: 50;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 16px;
  background: var(--ink-900);
  border: var(--bw) solid var(--cyan);
  box-shadow: var(--shadow-hard);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: opacity 0.22s ease, transform 0.22s ease, visibility 0.22s ease, background-color 0.16s ease;
}
.to-top[data-visible] { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { background: var(--gold); color: var(--ink-900); border-color: var(--ink-900); }

/* ---------- 7. 章节与网格 ---------- */
.section { position: relative; padding-block: var(--section-y); }
.section-paper { background: var(--paper); color: var(--slate); }
.section-paper h1,
.section-paper h2,
.section-paper h3 { color: var(--slate); }
.section-paper a { color: #10556B; text-decoration: underline; text-underline-offset: 3px; }
.section-paper a:hover { color: var(--band-wine); }

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(16px, 2.2vw, 30px);
}
.col-main { grid-column: 1 / span 7; }
.col-aside { grid-column: 9 / span 4; }

.index-num {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--gold);
}
.kicker {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--index);
  text-transform: uppercase;
}

/* ---------- 8. 卡片 ---------- */
.card {
  background: var(--ink-800);
  border: var(--bw) solid var(--edge);
  box-shadow: var(--shadow-hard);
  padding: clamp(18px, 2.2vw, 28px);
}
.card-title {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--paper);
  margin-bottom: 8px;
}
.section-paper .card {
  background: #FFFFFF;
  border-color: #C7CEE4;
  color: var(--slate);
  box-shadow: 6px 6px 0 rgba(42, 48, 80, 0.16);
}
.section-paper .card-title { color: var(--slate); }

/* ---------- 9. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 24px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.02em;
  border: var(--bw) solid transparent;
  transition: transform 0.16s ease, box-shadow 0.16s ease, background-color 0.16s ease, color 0.16s ease;
}
.btn-primary {
  background: var(--gold);
  color: var(--ink-900);
  border-color: var(--ink-900);
  box-shadow: var(--shadow-hard);
}
.btn-primary:hover { background: #FFC65A; transform: translate(-2px, -2px); box-shadow: 8px 8px 0 #05071A; }
.btn-ghost {
  background: transparent;
  color: var(--cyan);
  border-color: var(--cyan);
  box-shadow: var(--shadow-hard-cyan);
}
.btn-ghost:hover { background: rgba(53, 230, 208, 0.12); transform: translate(-2px, -2px); }
.btn:active { transform: translate(1px, 1px); }

/* ---------- 10. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 18px 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--index);
}
.breadcrumb li { display: inline-flex; align-items: center; gap: 8px; }
.breadcrumb li + li::before { content: "/"; color: var(--edge); }
.breadcrumb a:hover { color: var(--cyan); }
.breadcrumb [aria-current="page"] { color: var(--paper); }

/* ---------- 11. 章节色带 ---------- */
.chapter-band {
  background: var(--band-teal);
  border-block: var(--bw) solid #052527;
  padding-block: clamp(18px, 2.6vw, 30px);
}
.chapter-band[data-tone="wine"] { background: var(--band-wine); border-color: #2B0E1E; }
.band-inner {
  display: flex;
  align-items: baseline;
  gap: clamp(14px, 2vw, 26px);
  flex-wrap: wrap;
}
.chapter-index {
  font-family: var(--font-mono);
  font-size: clamp(26px, 4.6vw, 52px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--gold);
}
.chapter-title {
  font-size: clamp(19px, 2.6vw, 26px);
  font-weight: 800;
  color: var(--paper);
}
.chapter-band[data-reveal][data-visible] { animation: bandGrow 0.72s cubic-bezier(0.22, 0.8, 0.2, 1) both; }
@keyframes bandGrow {
  from { clip-path: inset(0 92% 0 0); }
  to { clip-path: inset(0 0 0 0); }
}

/* ---------- 12. 章节目录跟随 ---------- */
.chapter-nav {
  position: sticky;
  top: 110px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-left: 4px;
  border-left: var(--bw) solid var(--edge);
}
.chapter-nav-title {
  padding: 0 0 10px 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--index);
  text-transform: uppercase;
}
.chapter-link {
  position: relative;
  display: block;
  padding: 9px 12px 9px 16px;
  font-size: 14px;
  color: var(--index);
  transition: color 0.18s ease, background-color 0.18s ease;
}
.chapter-link::before {
  content: "";
  position: absolute;
  left: -2px;
  top: 7px;
  bottom: 7px;
  width: 3px;
  background: var(--cyan);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.24s ease;
}
.chapter-link:hover { color: var(--paper); background: rgba(53, 230, 208, 0.06); }
.chapter-link[aria-current="true"] { color: var(--paper); background: rgba(53, 230, 208, 0.09); }
.chapter-link[aria-current="true"]::before { transform: scaleY(1); }

/* ---------- 13. 图片容器 ---------- */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: linear-gradient(135deg, var(--ink-800) 0%, #101538 55%, var(--band-teal) 100%);
  border: var(--bw) solid var(--edge);
  box-shadow: var(--shadow-hard);
}
.media-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(53, 230, 208, 0.2) 1px, transparent 1px);
  background-size: 22px 22px;
  opacity: 0.75;
}
.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 28% 32%, rgba(53, 230, 208, 0.34), transparent 46%),
    radial-gradient(circle at 74% 70%, rgba(242, 180, 65, 0.26), transparent 44%);
}
.media-frame img {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame[data-ratio="4x3"] { aspect-ratio: 4 / 3; }
.media-frame[data-ratio="1x1"] { aspect-ratio: 1 / 1; }
.media-frame[data-ratio="21x9"] { aspect-ratio: 21 / 9; }

/* ---------- 14. 标签与提示 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid currentColor;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--index);
  text-transform: uppercase;
}
.tag-cyan { color: var(--cyan); }
.tag-gold { color: var(--gold); }
.tag-coral { color: var(--coral); }

.notice {
  padding: 16px 20px;
  border-left: 4px solid var(--coral);
  background: rgba(255, 107, 90, 0.1);
  color: #F2D5D0;
  font-size: 15px;
}
.notice[data-tone="calm"] {
  border-left-color: var(--cyan);
  background: rgba(53, 230, 208, 0.08);
  color: #CFE9E5;
}

/* ---------- 15. 对照表 ---------- */
.table-scroll { width: 100%; overflow-x: auto; }
.table-compare {
  min-width: 520px;
  border: var(--bw) solid var(--edge);
  background: var(--ink-800);
  font-size: 14.5px;
}
.table-compare caption {
  padding: 0 0 10px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--index);
}
.table-compare th,
.table-compare td {
  padding: 12px 14px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--edge);
}
.table-compare thead th {
  background: rgba(53, 230, 208, 0.08);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}
.table-compare tbody tr:nth-child(even) { background: rgba(11, 16, 48, 0.55); }
.table-compare tbody tr:last-child td { border-bottom: 0; }
.table-compare td[data-state="changed"] { color: var(--gold); }
.table-compare td[data-state="alert"] { color: var(--coral); }
.section-paper .table-compare {
  background: #FFFFFF;
  border-color: #C7CEE4;
  color: var(--slate);
}
.section-paper .table-compare th,
.section-paper .table-compare td { border-bottom-color: #DCE1EF; }

/* ---------- 16. 技能树式路径 ---------- */
.path-tree { display: flex; flex-direction: column; gap: 18px; }
.path-node { position: relative; padding-left: 26px; }
.path-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  width: 13px;
  height: 13px;
  background: var(--ink-900);
  border: var(--bw) solid var(--cyan);
}
.path-node::after {
  content: "";
  position: absolute;
  left: 6px;
  top: 24px;
  bottom: -18px;
  width: 2px;
  background: linear-gradient(180deg, rgba(53, 230, 208, 0.5), rgba(53, 230, 208, 0.08));
}
.path-node:last-child::after { display: none; }
.path-node-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  color: var(--paper);
}
.path-node-body { font-size: 15px; color: var(--text-mute); }

.node-field {
  background-image: radial-gradient(rgba(53, 230, 208, 0.16) 1px, transparent 1px);
  background-size: 26px 26px;
}

/* ---------- 17. 滚动显现 ---------- */
html.js-ready [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
html.js-ready [data-reveal][data-visible] { opacity: 1; transform: none; }

/* ---------- 18. 响应式 ---------- */
@media (max-width: 1100px) {
  .nav-link { font-size: 14px; }
}

@media (max-width: 940px) {
  .brand-status { display: none; }
  .nav-toggle { display: inline-flex; }
  .nav-cta { display: none; }

  .site-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(84vw, 340px);
    margin: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 94px 24px 32px;
    background: var(--ink-800);
    border-left: var(--bw) solid var(--cyan);
    box-shadow: -8px 0 0 rgba(5, 7, 26, 0.6);
    overflow-y: auto;
    transform: translateX(102%);
    visibility: hidden;
    transition: transform 0.28s ease, visibility 0.28s ease;
    z-index: 70;
  }
  .site-nav[data-open] { transform: translateX(0); visibility: visible; }

  .nav-list { flex-direction: column; align-items: stretch; gap: 0; }
  .nav-item { border-bottom: 1px solid var(--edge-soft); }
  .nav-link { display: block; padding: 16px 4px; font-size: 17px; }
  .nav-link::after { display: none; }
  .nav-link[aria-current="page"] {
    color: var(--gold);
    padding-left: 14px;
    box-shadow: inset 3px 0 0 var(--gold);
  }
  .nav-extra {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-top: 26px;
  }

  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
  .col-main,
  .col-aside { grid-column: 1 / -1; }
  .chapter-nav { position: static; top: auto; }
}

@media (max-width: 600px) {
  body { font-size: 16px; }
  .brand { font-size: 19px; }
  .header-inner { min-height: 72px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-base { justify-content: flex-start; }
  .footer-brand-name { font-size: 23px; }
  .to-top { padding: 9px 13px; font-size: 11px; }
  .chapter-index { font-size: 26px; }
}

/* ---------- 19. 无障碍降级 ---------- */
@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;
  }
  html.js-ready [data-reveal] { opacity: 1; transform: none; }
  .chapter-band[data-reveal][data-visible] { animation: none; }
  .scroll-progress { transition: none; }
}