:root {
  --color-surface: #292427;
  --color-surface-alt: #383236;
  --color-surface-deep: #4a4348;
  --color-ink: #cec0cb;
  --color-ink-soft: #a28b9d;
  --color-ink-muted: #8d7287;
  --color-line: #474045;
  --color-primary: #c936a7;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #3f2739;
  --color-accent: #1ce3c0;
  --color-accent-ink: #181116;
  --color-highlight: #274643;
  --color-focus: #0ff0c8;
  --color-contrast-surface: #f7f6f7;
  --color-contrast-ink: #3b353a;
  --color-contrast-line: #cecccd;
  --color-contrast-accent: #107f6c;
  --overlay-scrim: linear-gradient(180deg, rgba(247, 246, 247, 0.35) 0%, rgba(247, 246, 247, 0.72) 55%, rgba(247, 246, 247, 0.92) 100%);
  --font-heading: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-body: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --text-xs: 12.2px;
  --text-sm: 15.2px;
  --text-base: 17px;
  --text-lg: 21.2px;
  --text-xl: 26.6px;
  --text-2xl: 33.2px;
  --text-3xl: 41.5px;
  --text-4xl: 51.9px;
  --text-display: clamp(47px, 9.7vw, 124px);
  --text-figure: clamp(39px, 7.0vw, 89px);
  --weight-heading: 696;
  --weight-body: 400;
  --leading-body: 1.81;
  --leading-heading: 1.16;
  --tracking-heading: -0.006em;
  --radius-sm: 8px;
  --radius-md: 10px;
  --radius-lg: 12px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: 0 0 0 1px rgba(28, 227, 192, 0.35);
  --shadow-2: 0 0 28px rgba(28, 227, 192, 0.35);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1160px;
  --measure: 66ch;
  --gutter: 32px;
  --section-y: 96px;
  --section-y-lg: 134px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  background-color: var(--color-surface);
}

body {
  margin: 0;
  background-color: var(--color-surface);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: var(--weight-body);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img,
svg,
video,
canvas { display: block; max-width: 100%; height: auto; }

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

p { margin: 0 0 var(--space-3); }

a { color: inherit; text-decoration: none; }

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

button {
  margin: 0;
  padding: 0;
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

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

::selection {
  background-color: color-mix(in srgb, var(--color-primary) 55%, transparent);
  color: var(--color-primary-ink);
}

/* ========== 排版与容器 ========== */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--tight { padding-block: var(--space-8); }

.eyebrow {
  display: inline-block;
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
}

.section-title {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-2);
}

.section-sub {
  max-width: var(--measure);
  font-size: var(--text-lg);
  line-height: 1.55;
  color: var(--color-ink-soft);
  margin-bottom: 0;
}

.title-sm { font-size: var(--text-lg); margin-bottom: var(--space-1); }
.title-md { font-size: var(--text-xl); margin-bottom: var(--space-2); }

.lead {
  max-width: var(--measure);
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink-soft);
}

.mono,
.mono-tag,
.chapter-num,
.score,
.round-chip,
.footer-facts dd,
.footer-facts dt,
.breadcrumb__list,
.eyebrow,
.tag,
.entry__index,
.timeline__minute {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.mono-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
  white-space: nowrap;
}

.chapter-num {
  display: block;
  margin: 0 0 var(--space-1);
  font-size: var(--text-4xl);
  font-weight: 700;
  line-height: 1;
  color: var(--color-primary);
  text-shadow: 0 0 26px color-mix(in srgb, var(--color-primary) 45%, transparent);
}

/* 强调机制：色块高亮与彩色下划线 */
.mark {
  padding: 1px 5px;
  border-radius: 4px;
  background-color: var(--color-primary-soft);
  color: var(--color-ink);
}

.u-accent {
  text-decoration: underline;
  text-decoration-color: var(--color-accent);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

.u-primary {
  text-decoration: underline;
  text-decoration-color: var(--color-primary);
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

/* ========== 栅格与分栏 ========== */
.grid {
  display: grid;
  gap: var(--gutter);
  grid-template-columns: repeat(12, minmax(0, 1fr));
}

.grid > * { grid-column: span 12; }

.split {
  display: grid;
  gap: var(--gutter);
  grid-template-columns: minmax(0, 1fr);
}

@media (min-width: 900px) {
  .grid > .span-2 { grid-column: span 2; }
  .grid > .span-3 { grid-column: span 3; }
  .grid > .span-4 { grid-column: span 4; }
  .grid > .span-5 { grid-column: span 5; }
  .grid > .span-6 { grid-column: span 6; }
  .grid > .span-7 { grid-column: span 7; }
  .grid > .span-8 { grid-column: span 8; }
  .split--5-7 { grid-template-columns: 5fr 7fr; }
  .split--7-5 { grid-template-columns: 7fr 5fr; }
  .split--4-8 { grid-template-columns: 4fr 8fr; }
}

/* ========== 跳转链接 ========== */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -120px;
  z-index: 200;
  padding: 10px var(--space-2);
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  transition: top 180ms ease-out;
}

.skip-link:focus { top: var(--space-2); }

/* ========== 滚动进度 ========== */
.scroll-progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: 2px;
  z-index: 90;
  pointer-events: none;
  background-color: color-mix(in srgb, var(--color-line) 65%, transparent);
}

.scroll-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background-image: linear-gradient(90deg, var(--color-primary), var(--color-accent));
}

/* ========== 头部 ========== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background-color: color-mix(in srgb, var(--color-surface) 92%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.site-header::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 1px;
  background-image: linear-gradient(90deg, transparent, var(--color-primary) 20%, var(--color-accent) 62%, transparent);
  opacity: 0.7;
  pointer-events: none;
}

.header-frame__inner {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-height: 76px;
  padding-block: var(--space-2);
}

.brand-block {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.15;
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.brand__mark {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1;
  box-shadow: var(--shadow-1);
}

.brand__text { white-space: nowrap; }

.brand__tagline {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  letter-spacing: 0.02em;
  color: var(--color-ink-soft);
}

.nav-toggle {
  display: none;
  margin-left: auto;
  align-items: center;
  gap: var(--space-1);
  height: 40px;
  padding-inline: var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  color: var(--color-ink-soft);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  transition: color 200ms ease-out, border-color 200ms ease-out;
}

.nav-toggle:hover { color: var(--color-ink); border-color: var(--color-primary); }

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 16px;
  height: 2px;
  background-color: currentColor;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background-color: currentColor;
}

.nav-toggle__bars::before { top: -5px; }
.nav-toggle__bars::after { top: 5px; }

.site-nav { margin-left: auto; }

.site-nav__list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav__link {
  display: inline-flex;
  align-items: center;
  height: 38px;
  padding-inline: var(--space-2);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-sm);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-soft);
  transition: color 200ms ease-out, background-color 200ms ease-out, border-color 200ms ease-out;
}

.site-nav__link:hover {
  color: var(--color-ink);
  background-color: var(--color-surface-alt);
}

.site-nav__link[aria-current="page"] {
  color: var(--color-ink);
  background-color: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-accent) 55%, transparent);
  box-shadow: var(--shadow-1);
}

/* 轮次刻度带 */
.round-rail {
  position: relative;
  border-top: var(--border-thin) solid var(--color-line);
  background-color: color-mix(in srgb, var(--color-surface-alt) 72%, transparent);
}

.round-rail__inner {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding-block: 6px;
}

.round-rail__label {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
  white-space: nowrap;
}

.round-rail__track {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex: 1 1 auto;
  overflow-x: auto;
  padding-block: 5px;
  scrollbar-width: thin;
  scrollbar-color: var(--color-line) transparent;
  cursor: grab;
}

.round-rail__track.is-dragging { cursor: grabbing; }

.round-rail__track::-webkit-scrollbar { height: 4px; }
.round-rail__track::-webkit-scrollbar-thumb {
  background-color: var(--color-line);
  border-radius: var(--radius-pill);
}

.round-chip {
  flex: 0 0 auto;
  padding-bottom: 3px;
  border-bottom: var(--border-thin) solid var(--color-line);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
  white-space: nowrap;
  transition: color 180ms ease-out, border-color 180ms ease-out;
}

.round-chip[data-current] {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
  text-shadow: 0 0 14px color-mix(in srgb, var(--color-accent) 55%, transparent);
}

/* ========== 移动端导航 ========== */
@media (max-width: 900px) {
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    margin-left: 0;
    padding: var(--space-2) var(--gutter) var(--space-4);
    background-color: var(--color-surface-alt);
    border-bottom: var(--border-thin) solid var(--color-line);
    box-shadow: 0 18px 40px rgba(0, 0, 0, 0.45);
  }

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

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
  }

  .site-nav__link {
    height: 46px;
    padding-inline: var(--space-2);
    font-size: var(--text-base);
  }

  .brand__tagline { font-size: var(--text-sm); }
}

@media (max-width: 620px) {
  .header-frame__inner { min-height: 64px; }
  .brand__text { font-size: var(--text-base); }
  .round-rail__label { display: none; }
}

/* ========== 按钮 ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  min-height: 46px;
  padding-inline: var(--space-3);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-md);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  line-height: 1.25;
  transition: background-color 220ms ease-out, color 220ms ease-out, border-color 220ms ease-out, box-shadow 220ms ease-out;
}

.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  box-shadow: var(--shadow-1);
}

.btn--primary:hover {
  background-color: color-mix(in srgb, var(--color-primary) 82%, var(--color-primary-ink));
  box-shadow: var(--shadow-2);
}

.btn--ghost {
  border-color: color-mix(in srgb, var(--color-accent) 48%, transparent);
  background-color: color-mix(in srgb, var(--color-accent) 8%, transparent);
  color: var(--color-accent);
}

.btn--ghost:hover {
  background-color: color-mix(in srgb, var(--color-accent) 16%, transparent);
  box-shadow: var(--shadow-1);
}

/* ========== 面包屑 ========== */
.breadcrumb { padding-top: var(--space-4); }

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
}

.breadcrumb__list li + li::before {
  content: "/";
  margin-right: var(--space-1);
  color: var(--color-line);
}

.breadcrumb__list a:hover { color: var(--color-accent); }

/* ========== 正文长文档 ========== */
.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}

.prose h2 { font-size: var(--text-xl); margin-top: var(--space-6); }
.prose h3 { font-size: var(--text-lg); margin-top: var(--space-4); margin-bottom: var(--space-1); }

.prose ul,
.prose ol {
  margin: 0 0 var(--space-3);
  padding-left: 1.5em;
}

.prose ul li { list-style: square; }
.prose ol li { list-style: decimal; }
.prose li { margin-bottom: var(--space-1); }

.prose strong { font-weight: var(--weight-heading); color: var(--color-ink); }

.prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose > :last-child { margin-bottom: 0; }

/* ========== 条目容器 ========== */
.entry {
  position: relative;
  display: block;
  padding: var(--space-3);
  border: var(--border-thin) solid transparent;
  border-radius: var(--radius-lg);
  background-color: var(--color-surface-alt);
  transition: background-color 220ms ease-out, border-color 220ms ease-out, transform 220ms ease-out;
}

.entry:hover {
  background-color: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-primary) 58%, transparent);
  transform: translateY(-2px);
}

.entry--rail {
  border-radius: var(--radius-md);
  border-left: 2px solid var(--color-line);
  background-color: transparent;
  padding: var(--space-2) 0 var(--space-2) var(--space-3);
}

.entry--rail:hover {
  background-color: color-mix(in srgb, var(--color-surface-alt) 60%, transparent);
  border-left-color: var(--color-accent);
  transform: none;
}

.entry--flat {
  border-radius: 0;
  background-color: transparent;
  border-bottom: var(--border-thin) solid var(--color-line);
  padding: var(--space-3) 0;
}

.entry--flat:hover {
  background-color: transparent;
  border-bottom-color: var(--color-accent);
  transform: none;
}

.entry__index {
  display: block;
  margin-bottom: var(--space-1);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
}

.entry__title {
  font-size: var(--text-lg);
  margin-bottom: var(--space-1);
}

.entry__desc {
  margin: 0;
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-ink-soft);
}

.tag {
  display: inline-flex;
  align-items: center;
  height: 28px;
  padding-inline: var(--space-1);
  border-radius: var(--radius-sm);
  background-color: var(--color-highlight);
  color: color-mix(in srgb, var(--color-accent) 78%, var(--color-ink));
  font-size: var(--text-sm);
  line-height: 1.25;
  white-space: nowrap;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}

/* ========== 比分牌 ========== */
.scoreboard {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface-alt);
}

.scoreboard__team {
  flex: 1 1 140px;
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: 1.25;
}

.scoreboard__score {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: 700;
  line-height: 0.95;
  color: var(--color-accent);
  text-shadow: 0 0 30px color-mix(in srgb, var(--color-accent) 40%, transparent);
}

.scoreboard__meta {
  flex: 1 1 100%;
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
}

/* ========== 时间轴 ========== */
.timeline {
  position: relative;
  padding-left: var(--space-6);
}

.timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background-color: var(--color-line);
}

.timeline__item {
  position: relative;
  padding-bottom: var(--space-4);
}

.timeline__item::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--space-6) + 4px);
  top: 8px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background-color: var(--color-surface);
  border: 1px solid var(--color-line);
}

.timeline__item[data-current]::before {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-2);
}

.timeline__minute {
  display: block;
  margin-bottom: var(--space-1);
  font-size: var(--text-lg);
  line-height: 1.25;
  color: var(--color-accent);
}

.timeline__text {
  margin: 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

.timeline[data-collapsed] .timeline__item:nth-child(n + 7) { display: none; }

.timeline-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  min-height: 40px;
  margin-left: var(--space-6);
  padding-inline: var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-soft);
  transition: color 200ms ease-out, border-color 200ms ease-out;
}

.timeline-toggle:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* ========== 图片容器 ========== */
.media-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background-color: var(--color-surface-alt);
  aspect-ratio: 16 / 9;
}

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

.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(0.4) contrast(1.06) brightness(0.78);
}

.media-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image: linear-gradient(140deg, color-mix(in srgb, var(--color-primary) 44%, transparent), color-mix(in srgb, var(--color-accent) 26%, transparent));
  mix-blend-mode: color;
}

.media-frame--scrim::before { display: none; }

.media-frame--scrim::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image: var(--overlay-scrim);
}

.media-frame__caption {
  position: absolute;
  z-index: 2;
  left: var(--space-3);
  right: var(--space-3);
  bottom: var(--space-3);
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.4;
  color: var(--color-contrast-ink);
}

/* ========== 强对比区块 ========== */
.contrast-block {
  padding: var(--space-6);
  border-radius: var(--radius-lg);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.contrast-block h2,
.contrast-block h3,
.contrast-block h4 { color: var(--color-contrast-ink); }

.contrast-block .eyebrow { color: var(--color-contrast-accent); }

.contrast-block .section-sub,
.contrast-block p { color: color-mix(in srgb, var(--color-contrast-ink) 82%, var(--color-contrast-surface)); }

.contrast-block__num {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-contrast-accent);
}

.contrast-block table { border-color: var(--color-contrast-line); }

/* ========== 要点框 ========== */
.callout {
  padding: var(--space-3);
  border-radius: var(--radius-md);
  background-color: var(--color-highlight);
}

.callout__label {
  display: block;
  margin-bottom: var(--space-1);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  letter-spacing: 0.1em;
  color: var(--color-accent);
}

.callout p:last-child { margin-bottom: 0; }

/* ========== 侧边章节目录 ========== */
.toc {
  position: sticky;
  top: 152px;
  align-self: start;
  padding: var(--space-3);
  border-radius: var(--radius-lg);
  background-color: var(--color-surface-deep);
}

.toc__title {
  margin: 0 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}

.toc__list { display: grid; gap: 2px; }

.toc__link {
  display: block;
  padding: 8px var(--space-2);
  border-left: 2px solid transparent;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: var(--text-sm);
  line-height: 1.4;
  color: var(--color-ink-soft);
  transition: color 180ms ease-out, background-color 180ms ease-out, border-color 180ms ease-out;
}

.toc__link:hover { color: var(--color-ink); background-color: color-mix(in srgb, var(--color-surface-alt) 70%, transparent); }

.toc__link[aria-current="true"] {
  color: var(--color-ink);
  border-left-color: var(--color-focus);
  background-color: color-mix(in srgb, var(--color-focus) 10%, transparent);
}

@media (max-width: 900px) {
  .toc { position: static; top: auto; }
}

/* ========== 显现动效 ========== */
.reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 320ms ease-out, transform 320ms ease-out;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ========== 返回顶部 ========== */
.to-top {
  position: fixed;
  right: var(--space-3);
  bottom: var(--space-3);
  z-index: 80;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 10px var(--space-2);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-pill);
  background-color: var(--color-surface-deep);
  color: var(--color-ink-soft);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 240ms ease-out, transform 240ms ease-out, visibility 240ms, color 200ms ease-out, border-color 200ms ease-out;
}

.to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.to-top:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-1);
}

.to-top__arrow { font-size: var(--text-base); line-height: 1; }

/* ========== 页脚 ========== */
.site-footer {
  position: relative;
  margin-top: var(--space-8);
  border-top: var(--border-thin) solid var(--color-line);
  background-color: color-mix(in srgb, var(--color-surface-alt) 60%, var(--color-surface));
}

.footer-scale {
  position: relative;
  height: 20px;
  border-bottom: var(--border-thin) solid var(--color-line);
}

.footer-scale::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 1px;
  height: 7px;
  background-image: repeating-linear-gradient(to right, var(--color-line) 0 1px, transparent 1px 40px);
}

.footer-inner {
  display: grid;
  gap: var(--space-4) var(--gutter);
  padding-block: var(--space-6);
}

.footer-brand {
  display: inline-block;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.2;
  color: var(--color-ink);
}

.footer-brand:hover { color: var(--color-accent); }

.footer-brand__note {
  margin: var(--space-1) 0 4px;
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--color-ink-soft);
}

.footer-brand__meta {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
}

.footer-facts {
  margin: 0;
  display: grid;
  gap: 0;
  align-content: start;
}

.footer-facts__row {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding-block: 7px;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 75%, transparent);
}

.footer-facts__row:first-child { border-top: var(--border-thin) solid color-mix(in srgb, var(--color-line) 75%, transparent); }

.footer-facts dt {
  flex: 0 0 84px;
  font-size: var(--text-sm);
  line-height: 1.25;
  color: var(--color-ink-muted);
}

.footer-facts dd {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.4;
  color: var(--color-ink);
  overflow-wrap: anywhere;
}

.footer-nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  align-content: start;
}

.footer-nav__link {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  width: fit-content;
  border-bottom: var(--border-thin) solid transparent;
  font-size: var(--text-base);
  line-height: 1.3;
  color: var(--color-ink-soft);
  transition: color 200ms ease-out, border-color 200ms ease-out;
}

.footer-nav__link:hover {
  color: var(--color-accent);
  border-bottom-color: color-mix(in srgb, var(--color-accent) 60%, transparent);
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-1) var(--space-4);
  padding-block: var(--space-3);
  border-top: var(--border-thin) solid var(--color-line);
}

.footer-base__copy,
.footer-base__note {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.5;
  color: var(--color-ink-muted);
}

@media (min-width: 900px) {
  .footer-inner {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1.1fr) minmax(0, 0.8fr);
    align-items: start;
  }
}

/* ========== 无障碍与降级 ========== */
@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;
  }

  .reveal { opacity: 1; transform: none; }
  .to-top { transform: none; }
}