/* =======================================================
   完美体育在线 · 共享样式 /assets/site.css
   深海蓝底 · 战术板命令栏 · 荧光橙强调 · 等宽数据
   ======================================================= */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 78px;
}

body { margin: 0; }
img, svg { display: block; max-width: 100%; }
button { font: inherit; color: inherit; }
h1, h2, h3, h4, p, figure, blockquote { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
a { color: inherit; }

:root {
  /* ---------- 品牌色彩 ---------- */
  --deep: #08131F;
  --tactic: #102A43;
  --steel: #1E3A5F;
  --orange: #FF6B1A;
  --orange-soft: #FF8039;
  --lava: #C2410C;
  --jade: #17C08A;
  --cyan: #4FD1C5;
  --silver: #B9C4CE;
  --silver-dim: rgba(185, 196, 206, 0.72);
  --silver-line: rgba(185, 196, 206, 0.15);
  --mist: #F4F7F9;
  --graphite: #161B22;
  --grey: #7C8B99;
  --ink: #DDE6ED;

  /* ---------- 字体 ---------- */
  --font-display: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "SimSun", Georgia, serif;
  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, "Courier New", monospace;

  /* ---------- 尺寸 ---------- */
  --rail-w: 88px;
  --radius: 3px;
  --shell-max: 1180px;
  --shadow-float: 0 22px 44px -30px rgba(0, 0, 0, 0.95);
}

body {
  background: var(--deep);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  overflow-wrap: break-word;
  text-wrap: pretty;
  -webkit-font-smoothing: antialiased;
}

/* =======================================================
   1. 页头 · 纵向命令栏
   ======================================================= */

.skip-link {
  position: fixed;
  inset-block-start: 8px;
  inset-inline-start: 8px;
  z-index: 200;
  padding: 10px 16px;
  background: var(--orange);
  color: var(--deep);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-decoration: none;
  border-radius: var(--radius);
  transform: translateY(-160%);
  transition: transform 0.2s ease;
}
.skip-link:focus-visible {
  transform: translateY(0);
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.scroll-progress {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  height: 2px;
  width: 100%;
  z-index: 150;
  pointer-events: none;
  background: linear-gradient(90deg, var(--orange), var(--lava) 40%, var(--cyan));
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 0.12s linear;
}

.site-header { position: relative; z-index: 90; }

/* ---- 桌面命令栏 ---- */
.cmd-rail {
  position: fixed;
  inset-block: 0;
  inset-inline-start: 0;
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  padding: 16px 0 12px;
  background: linear-gradient(180deg, #102A43 0%, #0C2033 58%, #08131F 100%);
  border-inline-end: 1px solid var(--silver-line);
  z-index: 100;
}
.cmd-rail::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(
    135deg,
    rgba(79, 209, 197, 0.06) 0 1px,
    transparent 1px 17px
  );
}

.cmd-brand {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 9px;
  padding: 2px 6px 16px;
  margin-bottom: 4px;
  border-block-end: 1px solid var(--silver-line);
  text-decoration: none;
}
.cmd-brand__mark {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  background: var(--orange);
  color: var(--deep);
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: 17px;
  line-height: 1;
  clip-path: polygon(0 0, 100% 0, 100% 70%, 70% 100%, 0 100%);
}
.cmd-brand__text {
  display: block;
  max-width: 68px;
  font-size: 10px;
  line-height: 1.5;
  letter-spacing: 0.16em;
  text-align: center;
  color: var(--silver);
}
.cmd-brand__text em {
  display: block;
  font-style: normal;
  color: var(--cyan);
}

.cmd-nav { position: relative; flex: 1 1 auto; overflow-y: auto; }
.cmd-nav__list { display: flex; flex-direction: column; }
.cmd-nav__item { display: block; }

.cmd-link {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 11px 4px;
  text-decoration: none;
  color: var(--silver);
  border-inline-start: 2px solid transparent;
  transition: color 0.18s ease, background-color 0.18s ease, border-color 0.18s ease;
}
.cmd-link__idx {
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: rgba(185, 196, 206, 0.52);
  font-variant-numeric: tabular-nums;
}
.cmd-link__label {
  max-width: 74px;
  font-size: 10.5px;
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: 0.05em;
  text-align: center;
}
.cmd-link:hover {
  color: #FFFFFF;
  background: rgba(79, 209, 197, 0.09);
}
.cmd-link[aria-current="page"] {
  color: #FFFFFF;
  background: linear-gradient(90deg, rgba(255, 107, 26, 0.26), rgba(255, 107, 26, 0.02));
  border-inline-start-color: var(--orange);
}
.cmd-link[aria-current="page"] .cmd-link__idx { color: var(--orange); }

.cmd-cta {
  position: relative;
  display: block;
  margin: 10px 10px 12px;
  padding: 11px 4px;
  background: var(--orange);
  color: var(--deep);
  font-size: 11px;
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: 0.06em;
  text-align: center;
  text-decoration: none;
  border-radius: var(--radius);
  box-shadow: 0 14px 26px -18px rgba(255, 107, 26, 0.95);
  transition: background-color 0.18s ease, transform 0.18s ease;
}
.cmd-cta:hover { background: var(--orange-soft); transform: translateY(-1px); }
.cmd-cta:active { background: var(--lava); transform: none; }

.cmd-status {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 7px;
  margin-block-start: auto;
  padding: 12px 6px 2px;
  border-block-start: 1px solid var(--silver-line);
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--silver-dim);
  text-align: center;
}
.cmd-status__round b { color: var(--orange); font-weight: 600; }
.cmd-status__online { color: rgba(23, 192, 138, 0.92); }

.status-dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--jade);
  animation: pulse-dot 2.4s ease-out infinite;
}
@keyframes pulse-dot {
  0%   { box-shadow: 0 0 0 0 rgba(23, 192, 138, 0.55); }
  70%  { box-shadow: 0 0 0 7px rgba(23, 192, 138, 0); }
  100% { box-shadow: 0 0 0 0 rgba(23, 192, 138, 0); }
}

/* ---- 移动端顶栏 ---- */
.mobile-bar { display: none; }
.mobile-brand {
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.1em;
  color: #FFFFFF;
  text-decoration: none;
}
.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: transparent;
  border: 1px solid rgba(185, 196, 206, 0.32);
  border-radius: var(--radius);
  color: var(--mist);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
  cursor: pointer;
}
.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 3px;
  width: 14px;
}
.nav-toggle__bars i {
  display: block;
  height: 1.5px;
  width: 100%;
  background: currentColor;
  transition: transform 0.22s ease, opacity 0.22s ease;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1) { transform: translateY(4.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3) { transform: translateY(-4.5px) rotate(-45deg); }

@media (min-width: 901px) {
  body { padding-inline-start: var(--rail-w); }
  .scroll-progress { inset-inline-start: var(--rail-w); width: auto; inset-inline-end: 0; }
}

@media (max-width: 900px) {
  body { padding-block-start: 56px; }
  .scroll-progress { inset-block-start: 56px; }

  .mobile-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    position: fixed;
    inset-block-start: 0;
    inset-inline: 0;
    height: 56px;
    padding-inline: 16px;
    background: linear-gradient(180deg, #102A43, #0B1E30);
    border-block-end: 1px solid var(--silver-line);
    z-index: 120;
  }

  .cmd-rail {
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100dvh;
    padding: 68px 0 24px;
    overflow-y: auto;
    background: linear-gradient(180deg, #0E2438 0%, #08131F 100%);
    border-inline-end: 0;
    transform: translateX(-100%);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.28s ease, opacity 0.28s ease, visibility 0.28s ease;
  }
  .cmd-rail[data-open] {
    transform: none;
    opacity: 1;
    visibility: visible;
  }

  .cmd-brand {
    flex-direction: row;
    justify-content: flex-start;
    gap: 12px;
    padding: 0 20px 16px;
  }
  .cmd-brand__text { max-width: none; text-align: start; font-size: 12px; letter-spacing: 0.14em; }
  .cmd-brand__text em { display: inline; margin-inline-start: 2px; }

  .cmd-nav { overflow: visible; }
  .cmd-link {
    flex-direction: row;
    align-items: baseline;
    justify-content: flex-start;
    gap: 14px;
    padding: 15px 20px;
    border-inline-start: 0;
    border-block-end: 1px solid rgba(185, 196, 206, 0.1);
  }
  .cmd-link__idx { font-size: 11px; }
  .cmd-link__label { max-width: none; font-size: 15px; text-align: start; letter-spacing: 0.03em; }
  .cmd-link[aria-current="page"] {
    border-inline-start: 0;
    border-inline-end: 2px solid var(--orange);
    background: linear-gradient(270deg, rgba(255, 107, 26, 0.2), rgba(255, 107, 26, 0.02));
  }

  .cmd-cta { margin: 18px 20px 14px; padding: 14px 8px; font-size: 13px; }
  .cmd-status { flex-direction: row; justify-content: center; gap: 12px; padding: 14px 20px 0; font-size: 10px; }
}

/* =======================================================
   2. 页脚
   ======================================================= */

.site-footer {
  position: relative;
  margin-block-start: 0;
  padding: clamp(38px, 5vw, 68px) clamp(20px, 4vw, 56px) 0;
  background: linear-gradient(180deg, #0B1B2B 0%, #08131F 72%);
  border-block-start: 1px solid var(--silver-line);
}
.site-footer::before {
  content: "";
  position: absolute;
  inset-block-start: 0;
  inset-inline-start: 0;
  width: min(280px, 42%);
  height: 2px;
  background: linear-gradient(90deg, var(--orange), rgba(255, 107, 26, 0));
}

.footer-grid {
  display: grid;
  gap: clamp(26px, 3vw, 48px);
  grid-template-columns: 1.5fr 0.85fr 1.3fr 0.85fr;
  max-width: var(--shell-max);
  margin-inline: auto;
}

.footer-col { min-width: 0; }

.footer-brand {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 800;
  letter-spacing: 0.1em;
  color: #FFFFFF;
  text-decoration: none;
}
.footer-brand:hover { color: var(--orange); }

.footer-line {
  margin-block-start: 10px;
  max-width: 24em;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--silver-dim);
}

.footer-round {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-block-start: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--silver-dim);
}

.footer-title {
  margin-block-end: 14px;
  padding-block-end: 8px;
  border-block-end: 1px solid var(--silver-line);
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--silver);
}

.footer-list { display: flex; flex-direction: column; gap: 9px; }
.footer-list a {
  font-size: 13.5px;
  color: #CBD6E0;
  text-decoration: none;
  transition: color 0.16s ease, padding-inline-start 0.16s ease;
}
.footer-list a:hover { color: var(--orange); padding-inline-start: 3px; }

.footer-contact { display: flex; flex-direction: column; gap: 10px; margin-block-start: 14px; }
.footer-contact li {
  display: grid;
  grid-template-columns: 42px 1fr;
  gap: 10px;
  align-items: baseline;
  font-size: 13px;
  line-height: 1.6;
}
.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--cyan);
  text-transform: uppercase;
}
.footer-contact__value { color: #CBD6E0; word-break: break-word; }

.to-top {
  position: fixed;
  inset-block-end: 22px;
  inset-inline-end: 22px;
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid rgba(185, 196, 206, 0.34);
  background: rgba(16, 42, 67, 0.94);
  color: var(--mist);
  font-family: var(--font-mono);
  font-size: 16px;
  cursor: pointer;
  z-index: 130;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.24s ease, transform 0.24s ease, color 0.18s ease, border-color 0.18s ease, visibility 0.24s ease;
}
.to-top[data-visible] { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { color: var(--orange); border-color: var(--orange); }

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  max-width: var(--shell-max);
  margin: clamp(32px, 4vw, 56px) auto 0;
  padding-block: 18px 22px;
  border-block-start: 1px solid var(--silver-line);
  font-size: 12px;
  letter-spacing: 0.03em;
  color: var(--silver-dim);
}
.footer-base__copy { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
.footer-base__icp { font-family: var(--font-mono); color: var(--silver); }
.footer-base__note { color: rgba(185, 196, 206, 0.62); }

@media (max-width: 1100px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .footer-grid { grid-template-columns: 1fr; }
  .footer-base { flex-direction: column; align-items: flex-start; }
  .to-top { inset-block-end: 16px; inset-inline-end: 16px; width: 42px; height: 42px; }
}

/* =======================================================
   3. 通用排版 / 容器 / 区块
   ======================================================= */

.container {
  width: min(var(--shell-max), 100% - clamp(32px, 6vw, 80px));
  margin-inline: auto;
}

.section { padding-block: clamp(48px, 7vw, 96px); }

.section--light {
  background: var(--mist);
  color: var(--graphite);
}
.section--light .display { color: var(--deep); }
.section--light .lead { color: #3C4A57; }
.section--light .module-title { color: var(--deep); }
.section--light .eyebrow { color: var(--lava); border-block-end-color: rgba(22, 27, 34, 0.2); }
.section--light .panel {
  background: #FFFFFF;
  border-color: rgba(22, 27, 34, 0.1);
  box-shadow: 0 20px 44px -38px rgba(8, 19, 31, 0.7);
}
.section--light .stat__label { color: var(--grey); }
.section--light .figure__caption { color: var(--grey); }
.section--light .rule { background: linear-gradient(90deg, var(--lava), rgba(22, 27, 34, 0.15), transparent); }

.section-head {
  display: flex;
  flex-direction: column;
  gap: 14px;
  max-width: 48rem;
  margin-block-end: clamp(24px, 3vw, 44px);
}

.display {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2rem, 4.2vw, 3.6rem);
  line-height: 1.12;
  letter-spacing: -0.005em;
  color: #FFFFFF;
}

.eyebrow {
  display: inline-block;
  padding-block-end: 6px;
  border-block-end: 1px solid rgba(185, 196, 206, 0.32);
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
}

.lead {
  max-width: 38em;
  font-size: clamp(1rem, 1.4vw, 1.125rem);
  line-height: 1.8;
  color: var(--silver);
}

.module-title {
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: clamp(1.125rem, 1.6vw, 1.5rem);
  line-height: 1.35;
  letter-spacing: 0.02em;
  color: #FFFFFF;
}

.rule {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, rgba(255, 107, 26, 0.66), rgba(185, 196, 206, 0.2), transparent);
}

/* =======================================================
   4. 面包屑
   ======================================================= */

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--silver-dim);
}
.breadcrumb a { text-decoration: none; color: var(--silver-dim); }
.breadcrumb a:hover { color: var(--cyan); }
.breadcrumb__sep { color: rgba(185, 196, 206, 0.38); }
.section--light .breadcrumb,
.section--light .breadcrumb a { color: var(--grey); }

/* =======================================================
   5. 网格与 Bento 模块
   ======================================================= */

.bento {
  display: grid;
  gap: clamp(12px, 1.6vw, 20px);
  grid-template-columns: repeat(12, minmax(0, 1fr));
}

.grid-2 {
  display: grid;
  gap: clamp(16px, 2.4vw, 32px);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.grid-3 {
  display: grid;
  gap: clamp(16px, 2.4vw, 32px);
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.panel {
  position: relative;
  padding: clamp(16px, 2.2vw, 26px);
  background: linear-gradient(165deg, rgba(30, 58, 95, 0.55), rgba(8, 19, 31, 0.92));
  border: 1px solid var(--silver-line);
  border-radius: var(--radius);
  min-width: 0;
}
.panel--flat { background: rgba(16, 42, 67, 0.52); }
.panel--accent {
  background: linear-gradient(150deg, rgba(255, 107, 26, 0.18), rgba(8, 19, 31, 0.92));
  border-color: rgba(255, 107, 26, 0.38);
}

/* =======================================================
   6. 数据统计
   ======================================================= */

.stat { display: flex; flex-direction: column; gap: 6px; }
.stat__num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(2.5rem, 4.5vw, 4rem);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}
.stat__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--silver-dim);
  text-transform: uppercase;
}

/* =======================================================
   7. 图片容器基础（页面阶段放 img）
   ======================================================= */

.figure { display: flex; flex-direction: column; gap: 10px; min-width: 0; }
.figure__img {
  position: relative;
  display: grid;
  place-items: center;
  overflow: hidden;
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 1px solid rgba(185, 196, 206, 0.16);
  border-radius: var(--radius);
  background:
    repeating-linear-gradient(135deg, rgba(79, 209, 197, 0.1) 0 1px, transparent 1px 15px),
    linear-gradient(160deg, #16324F 0%, #0A1A29 62%, #123049 100%);
}
.figure__img > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.figure__img--wide { aspect-ratio: 21 / 9; }
.figure__img--tall { aspect-ratio: 3 / 4; }

.figure__tag {
  position: absolute;
  inset-block-start: 10px;
  inset-inline-start: 10px;
  padding: 4px 9px;
  background: rgba(8, 19, 31, 0.82);
  border: 1px solid rgba(255, 107, 26, 0.5);
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--orange);
}

.figure__caption {
  font-size: 12.5px;
  line-height: 1.6;
  letter-spacing: 0.02em;
  color: var(--silver-dim);
}

/* =======================================================
   8. 按钮 / 胶囊筛选
   ======================================================= */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease, transform 0.18s ease;
}
.btn--primary {
  background: var(--orange);
  color: var(--deep);
  box-shadow: 0 16px 30px -22px rgba(255, 107, 26, 0.95);
}
.btn--primary:hover { background: var(--orange-soft); transform: translateY(-1px); }
.btn--primary:active { background: var(--lava); transform: none; }
.btn--ghost {
  background: transparent;
  border-color: rgba(185, 196, 206, 0.34);
  color: var(--mist);
}
.btn--ghost:hover { border-color: var(--cyan); color: #FFFFFF; background: rgba(79, 209, 197, 0.08); }
.btn--quiet {
  padding: 6px 0;
  background: transparent;
  color: var(--silver);
  text-decoration: underline;
  text-underline-offset: 4px;
}
.btn--quiet:hover { color: var(--orange); }

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border: 1px solid rgba(185, 196, 206, 0.28);
  border-radius: 999px;
  background: transparent;
  color: var(--silver);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.03em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.16s ease, border-color 0.16s ease, color 0.16s ease;
}
.chip:hover { border-color: var(--cyan); color: #FFFFFF; }
.chip[aria-pressed="true"],
.chip[aria-selected="true"] {
  background: var(--orange);
  border-color: var(--orange);
  color: var(--deep);
}

/* =======================================================
   9. 章节索引（长页右缘目录）
   ======================================================= */

.chapter-index {
  position: sticky;
  inset-block-start: 32px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-inline-start: 14px;
  border-inline-start: 1px solid rgba(185, 196, 206, 0.2);
}
.chapter-link {
  margin-inline-start: -16px;
  padding: 5px 0 5px 14px;
  border-inline-start: 2px solid transparent;
  font-size: 12.5px;
  line-height: 1.5;
  letter-spacing: 0.02em;
  color: var(--silver-dim);
  text-decoration: none;
  transition: color 0.16s ease, border-color 0.16s ease;
}
.chapter-link:hover { color: #FFFFFF; }
.chapter-link[aria-current="true"] {
  color: var(--orange);
  border-inline-start-color: var(--orange);
}

/* =======================================================
   10. 进入视口显现
   ======================================================= */

[data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
[data-reveal].is-inview { opacity: 1; transform: none; }

/* =======================================================
   11. 响应式细节 & 无障碍
   ======================================================= */

@media (max-width: 900px) {
  .grid-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .chapter-index { position: static; border-inline-start: 0; padding-inline-start: 0; flex-direction: row; flex-wrap: wrap; gap: 8px; }
  .chapter-link {
    margin-inline-start: 0;
    padding: 6px 12px;
    border: 1px solid rgba(185, 196, 206, 0.24);
    border-radius: 999px;
  }
  .chapter-link[aria-current="true"] { border-color: var(--orange); }
}

@media (max-width: 640px) {
  .grid-2, .grid-3 { grid-template-columns: minmax(0, 1fr); }
  .figure__img--wide { aspect-ratio: 16 / 9; }
}

@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;
  }
  .status-dot { animation: none; box-shadow: 0 0 0 3px rgba(23, 192, 138, 0.22); }
  [data-reveal] { opacity: 1; transform: none; }
  .scroll-progress { transition: none; }
}