:root {
  --color-surface: #f2f3f3;
  --color-surface-alt: #e9eaea;
  --color-surface-deep: #dcdede;
  --color-ink: #394644;
  --color-ink-soft: #5a6d6a;
  --color-ink-muted: #758a87;
  --color-line: #d1d4d4;
  --color-primary: #3b8277;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #d8e3e2;
  --color-accent: #bc4387;
  --color-accent-ink: #ffffff;
  --color-highlight: #e8d3e0;
  --color-focus: #c13483;
  --color-contrast-surface: #161e1d;
  --color-contrast-ink: #e4e7e6;
  --color-contrast-line: #434a49;
  --color-contrast-accent: #c7619a;
  --overlay-scrim: linear-gradient(180deg, rgba(22, 30, 29, 0.35) 0%, rgba(22, 30, 29, 0.72) 55%, rgba(22, 30, 29, 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: 14.6px;
  --text-base: 16px;
  --text-lg: 19.2px;
  --text-xl: 23.0px;
  --text-2xl: 27.6px;
  --text-3xl: 33.2px;
  --text-4xl: 39.8px;
  --text-display: clamp(35px, 7.3vw, 93px);
  --text-figure: clamp(29px, 5.2vw, 67px);
  --weight-heading: 627;
  --weight-body: 400;
  --leading-body: 1.83;
  --leading-heading: 1.19;
  --tracking-heading: -0.004em;
  --radius-sm: 3px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-pill: 999px;
  --border-thin: 1px;
  --border-thick: 2px;
  --shadow-1: 0 1px 0 rgba(57, 70, 68, 0.12);
  --shadow-2: 0 2px 0 rgba(57, 70, 68, 0.18);
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1200px;
  --measure: 73ch;
  --gutter: 32px;
  --section-y: 94px;
  --section-y-lg: 132px;
}

/* 派生字体栈：长文正文切到宋体类衬线，标题与界面层保持无衬线，形成中西混排 */
:root {
  --font-serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "STSong", "SimSun", serif;
  --warm-band: linear-gradient(180deg, color-mix(in srgb, var(--color-accent) 10%, transparent), color-mix(in srgb, var(--color-accent) 4%, transparent));
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: 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);
}
h1, h2, h3, h4, h5 {
  margin: 0;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
}
p, ul, ol, figure, blockquote, dl, dd { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
table { border-collapse: collapse; width: 100%; }
:focus-visible {
  outline: var(--border-thick) solid var(--color-focus);
  outline-offset: 2px;
  box-shadow: inset 0 0 0 1px var(--color-focus);
}
main [id] { scroll-margin-top: 128px; }

/* ---------- 布局 ---------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(20px, 4vw, var(--gutter));
}
.section { padding-block: var(--section-y); }
.section--lg { padding-block: var(--section-y-lg); }
.section--contrast {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-block: var(--border-thick) solid var(--color-primary);
}
.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
}
.grid > * { min-width: 0; }
.col-3 { grid-column: span 3; }
.col-4 { grid-column: span 4; }
.col-6 { grid-column: span 6; }
.col-8 { grid-column: span 8; }
.col-12 { grid-column: span 12; }
.layout-split {
  display: grid;
  grid-template-columns: minmax(240px, 320px) minmax(0, 1fr);
  gap: var(--space-6);
  align-items: start;
}

/* ---------- 文字阶梯 ---------- */
.display-title {
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 0.98;
  letter-spacing: 0.01em;
}
.figure-num {
  font-family: var(--font-heading);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--color-primary);
}
.prose {
  font-family: var(--font-serif);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  max-width: var(--measure);
  color: var(--color-ink);
}
.prose h2, .prose h3, .prose h4 { font-family: var(--font-heading); }
.prose p + p { margin-top: var(--space-2); }
.prose strong { color: var(--color-primary); font-weight: 700; }
.prose a { color: var(--color-accent); border-bottom: var(--border-thin) solid currentColor; }
.rule { border: 0; border-top: var(--border-thin) solid var(--color-line); margin: 0; }
.rule--thick { border-top: var(--border-thick) solid var(--color-ink); }
.rule--double { position: relative; border-top: var(--border-thick) solid var(--color-ink); }
.rule--double::after {
  content: "";
  position: absolute;
  left: 0; right: 0; top: 3px;
  border-top: var(--border-thin) solid var(--color-line);
}

/* ---------- 编号章节头 ---------- */
.section-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: end;
  gap: var(--space-3);
  border-top: var(--border-thick) solid var(--color-ink);
  padding-top: var(--space-2);
  margin-bottom: var(--space-4);
}
.section-head__index {
  font-family: var(--font-mono);
  font-size: var(--text-4xl);
  line-height: 0.9;
  letter-spacing: -0.02em;
  color: var(--color-primary);
}
.section-head__title { font-size: var(--text-2xl); }
.section-head__note {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  max-width: 34ch;
  justify-self: end;
  text-align: right;
}

/* ---------- 编号轨道 ---------- */
.index-track {
  display: flex;
  flex-direction: column;
  gap: 2px;
  border-top: var(--border-thick) solid var(--color-ink);
  padding-top: var(--space-2);
  background-image: var(--warm-band);
  background-color: var(--color-surface-alt);
  background-repeat: no-repeat;
  background-size: 100% 6px;
  padding-inline: var(--space-1);
  padding-bottom: var(--space-1);
  border-radius: var(--radius-sm);
}
.index-track__item {
  display: flex;
  align-items: baseline;
  gap: var(--space-2);
  padding: 10px var(--space-2);
  border-radius: var(--radius-sm);
  border-left: var(--border-thick) solid transparent;
  background: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  transition: background-color 0.16s ease, color 0.16s ease, transform 0.16s ease, border-color 0.16s ease;
}
.index-track__item:hover {
  background: var(--color-surface-deep);
  color: var(--color-ink);
  transform: translateX(2px);
}
.index-track__item[data-active],
.index-track__item[aria-current="true"] {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-left-color: var(--color-accent);
}
.index-track__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  opacity: 0.85;
}
.index-track__label { font-family: var(--font-heading); letter-spacing: 0.02em; }

/* ---------- 引述强调 ---------- */
.pull-quote {
  margin: var(--space-4) 0;
  padding: var(--space-3) var(--space-3) var(--space-3) var(--space-4);
  border-left: var(--border-thick) solid var(--color-accent);
  background-color: var(--color-highlight);
  background-image: var(--warm-band);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-family: var(--font-serif);
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink);
  text-indent: 2ch;
  max-width: var(--measure);
}
.pull-quote::first-line { font-weight: 700; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 11px 18px;
  border-radius: var(--radius-md);
  border: var(--border-thin) solid transparent;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.03em;
  line-height: 1.2;
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease, transform 0.16s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn--primary {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-color: var(--color-primary);
}
.btn--primary:hover { background: color-mix(in srgb, var(--color-primary) 84%, var(--color-contrast-surface)); }
.btn--accent {
  background: var(--color-accent);
  color: var(--color-accent-ink);
  border-color: var(--color-accent);
}
.btn--accent:hover { background: color-mix(in srgb, var(--color-accent) 84%, var(--color-contrast-surface)); }
.btn--ghost {
  background: transparent;
  color: var(--color-ink);
  border-color: var(--color-line);
}
.btn--ghost:hover { background: var(--color-surface-alt); border-color: var(--color-ink-muted); }
.btn--sm { padding: 8px 14px; font-size: var(--text-xs); }

/* ---------- 标签与状态点 ---------- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  border: var(--border-thin) solid currentColor;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  line-height: 1.4;
  white-space: nowrap;
}
.chip--quiet {
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-line);
  background: color-mix(in srgb, var(--color-contrast-ink) 7%, transparent);
}
.chip--live {
  color: var(--color-contrast-accent);
  border-color: color-mix(in srgb, var(--color-contrast-accent) 60%, transparent);
  background: color-mix(in srgb, var(--color-contrast-accent) 12%, transparent);
}
.status-dot {
  flex: none;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-contrast-accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-contrast-accent) 26%, transparent);
}

/* ---------- 面包屑 ---------- */
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  color: var(--color-ink-muted);
  padding-block: var(--space-2);
}
.breadcrumbs__item { display: inline-flex; align-items: center; gap: var(--space-1); }
.breadcrumbs__item + .breadcrumbs__item::before {
  content: "/";
  color: var(--color-line);
}
.breadcrumbs__item a:hover { color: var(--color-primary); }

/* ---------- 图片容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  border: var(--border-thin) solid var(--color-line);
  background: var(--color-surface-deep);
  isolation: isolate;
}
.media-frame__img {
  width: 100%;
  height: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}
.media-frame--tall .media-frame__img { aspect-ratio: 4 / 5; }
.media-frame__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
  pointer-events: none;
}
.media-frame__body {
  position: absolute;
  inset: auto 0 0 0;
  padding: var(--space-4);
  color: var(--color-contrast-ink);
}
.media-frame__body h3 { font-size: var(--text-xl); }
.media-frame__body p {
  margin-top: var(--space-1);
  font-size: var(--text-sm);
  font-family: var(--font-serif);
  color: color-mix(in srgb, var(--color-contrast-ink) 82%, transparent);
}

/* ---------- 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: var(--color-surface);
}
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -80px;
  z-index: 90;
  padding: 10px 16px;
  border-radius: var(--radius-md);
  background: var(--color-accent);
  color: var(--color-accent-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  transition: top 0.16s ease;
}
.skip-link:focus { top: var(--space-2); }
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: var(--border-thick);
  background: var(--color-contrast-line);
  overflow: hidden;
  z-index: 3;
}
.scroll-progress__bar {
  display: block;
  height: 100%;
  width: 100%;
  transform: scaleX(var(--scroll-progress, 0));
  transform-origin: left center;
  background: linear-gradient(90deg, var(--color-primary), var(--color-contrast-accent), var(--color-accent));
  transition: transform 0.12s linear;
}
.status-rail {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thick) solid var(--color-primary);
}
.status-rail__inner {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding-block: 7px;
  min-height: 44px;
}
.status-rail__line {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: var(--text-xs);
  letter-spacing: 0.02em;
  color: var(--color-contrast-ink);
  min-width: 0;
}
.status-rail__meta {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.vert-mark {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  line-height: 1;
  color: var(--color-contrast-accent);
  border-left: var(--border-thin) solid var(--color-contrast-line);
  padding-left: var(--space-1);
}
.nav-rail {
  position: relative;
  background: var(--color-surface);
  border-bottom: var(--border-thick) solid var(--color-ink);
}
.nav-rail::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -4px;
  height: var(--border-thin);
  background: var(--color-line);
}
.nav-rail__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  min-height: 76px;
  padding-block: 10px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: none;
}
.brand__mark {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: var(--color-primary);
  color: var(--color-primary-ink);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: 700;
  border-bottom: var(--border-thick) solid var(--color-accent);
}
.brand__text { display: flex; flex-direction: column; line-height: 1.2; }
.brand__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  letter-spacing: 0.08em;
}
.brand__sub {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-1);
  padding: 9px 12px;
  border-radius: var(--radius-md);
  border: var(--border-thin) solid var(--color-line);
  background: var(--color-surface-alt);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
}
.nav-toggle__bars { display: grid; gap: 3px; }
.nav-toggle__bars i {
  display: block;
  width: 18px;
  height: var(--border-thick);
  background: currentColor;
  transition: transform 0.16s ease, opacity 0.16s ease;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1) { transform: translateY(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(-5px) rotate(-45deg); }
.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}
.site-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}
.site-nav__link {
  display: inline-flex;
  align-items: center;
  padding: 8px 11px;
  border-radius: var(--radius-sm);
  border-bottom: var(--border-thick) solid transparent;
  color: var(--color-ink-soft);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.03em;
  transition: background-color 0.16s ease, color 0.16s ease, border-color 0.16s ease;
}
.site-nav__link:hover { background: var(--color-surface-alt); color: var(--color-ink); }
.site-nav__link[aria-current="page"] {
  background: var(--color-primary);
  color: var(--color-primary-ink);
  border-bottom-color: var(--color-accent);
}
.site-nav__cta {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding-left: var(--space-3);
  border-left: var(--border-thin) solid var(--color-line);
}

/* ---------- 移动端拇指操作区 ---------- */
.thumb-bar {
  display: none;
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 70;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  background: var(--color-contrast-surface);
  border-top: var(--border-thick) solid var(--color-primary);
  box-shadow: var(--shadow-2);
  padding-bottom: env(safe-area-inset-bottom, 0px);
}
.thumb-bar__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  padding: 9px 4px;
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  border-right: var(--border-thin) solid var(--color-contrast-line);
}
.thumb-bar__item:last-child { border-right: 0; }
.thumb-bar__item:active { background: color-mix(in srgb, var(--color-primary) 34%, transparent); }
.thumb-bar__icon {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--color-contrast-accent);
}

/* ---------- 页脚 ---------- */
.site-footer {
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: var(--border-thick) solid var(--color-primary);
  margin-top: var(--section-y);
}
.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-4);
  padding-block: var(--space-3);
  font-size: var(--text-sm);
}
.footer-rule {
  flex: none;
  width: var(--border-thick);
  height: 22px;
  background: var(--color-contrast-accent);
}
.site-footer__brand {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  letter-spacing: 0.08em;
}
.site-footer__links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}
.site-footer__links a {
  color: var(--color-contrast-ink);
  border-bottom: var(--border-thin) solid var(--color-contrast-line);
  padding-bottom: 2px;
  transition: color 0.16s ease, border-color 0.16s ease;
}
.site-footer__links a:hover { color: var(--color-contrast-accent); border-color: var(--color-contrast-accent); }
.site-footer__meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: color-mix(in srgb, var(--color-contrast-ink) 72%, transparent);
}
.footer-tag {
  margin-left: auto;
  transform: rotate(-3deg);
  padding: 3px 9px;
  border: var(--border-thin) dashed var(--color-contrast-line);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--color-contrast-accent);
}

/* ---------- 平板 ---------- */
@media (max-width: 1080px) {
  .section-head { grid-template-columns: auto minmax(0, 1fr); }
  .section-head__note { grid-column: 2; justify-self: start; text-align: left; }
  .layout-split { grid-template-columns: minmax(200px, 260px) minmax(0, 1fr); gap: var(--space-4); }
}

@media (max-width: 900px) {
  :root { --section-y: 64px; }
  .grid { gap: var(--space-3); }
  .col-3, .col-4, .col-6, .col-8 { grid-column: span 12; }
  .layout-split { grid-template-columns: minmax(0, 1fr); }
  .nav-toggle { display: inline-flex; }
  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--color-surface);
    border-top: var(--border-thick) solid var(--color-ink);
    border-bottom: var(--border-thick) solid var(--color-ink);
    padding: var(--space-2) clamp(20px, 4vw, var(--gutter)) var(--space-3);
    max-height: 72vh;
    overflow: auto;
    z-index: 55;
  }
  .site-nav[data-open] { display: flex; }
  .site-nav__list { flex-direction: column; align-items: stretch; gap: 0; }
  .site-nav__link {
    width: 100%;
    padding: 14px 10px;
    border-radius: 0;
    border-bottom: var(--border-thin) solid var(--color-line);
    font-size: var(--text-base);
  }
  .site-nav__link[aria-current="page"] { border-bottom-color: var(--color-accent); }
  .site-nav__cta { display: none; }
  .thumb-bar { display: grid; }
  body { padding-bottom: 62px; }
  .status-rail__inner { gap: var(--space-2); }
  .vert-mark { display: none; }
  .status-rail__line {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  .status-rail__meta { display: none; }
  .nav-rail__inner { min-height: 62px; }
  .footer-tag { margin-left: 0; }
  .site-footer { margin-top: var(--space-8); }
  .pull-quote { font-size: var(--text-base); }
}

@media (max-width: 520px) {
  .brand__mark { width: 34px; height: 34px; font-size: var(--text-base); }
  .brand__name { font-size: var(--text-lg); }
  .brand__sub { display: none; }
  .section-head__index { font-size: var(--text-3xl); }
  .media-frame--tall .media-frame__img { aspect-ratio: 16 / 9; }
}

/* ---------- 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
  }
  .btn:hover, .index-track__item:hover { transform: none; }
  .scroll-progress__bar { transition: none; }
}