:root {
  --color-surface: #f7f7f7;
  --color-surface-alt: #efeeee;
  --color-surface-deep: #e3e2e1;
  --color-ink: #4f4640;
  --color-ink-soft: #756961;
  --color-ink-muted: #8b7d74;
  --color-line: #d9d7d6;
  --color-primary: #af612c;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #ede2db;
  --color-accent: #2877c8;
  --color-accent-ink: #ffffff;
  --color-highlight: #d2e0ef;
  --color-focus: #1a70c6;
  --color-contrast-surface: #201812;
  --color-contrast-ink: #e7e5e4;
  --color-contrast-line: #4c4540;
  --color-contrast-accent: #3384d6;
  --overlay-scrim: linear-gradient(180deg, rgba(32, 24, 18, 0.35) 0%, rgba(32, 24, 18, 0.72) 55%, rgba(32, 24, 18, 0.92) 100%);
  --font-heading: "Songti SC", "Source Han Serif SC", "Noto Serif SC", SimSun, serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 12.9px;
  --text-sm: 16.1px;
  --text-base: 18px;
  --text-lg: 22.5px;
  --text-xl: 28.1px;
  --text-2xl: 35.2px;
  --text-3xl: 43.9px;
  --text-4xl: 54.9px;
  --text-display: clamp(34px, 6.0vw, 77px);
  --text-figure: clamp(28px, 4.3vw, 55px);
  --weight-heading: 698;
  --weight-body: 400;
  --leading-body: 1.84;
  --leading-heading: 1.21;
  --tracking-heading: -0.008em;
  --radius-sm: 0px;
  --radius-md: 1px;
  --radius-lg: 2px;
  --radius-pill: 2px;
  --border-thin: 1px;
  --border-thick: 1px;
  --shadow-1: none;
  --shadow-2: none;
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-6: 48px;
  --space-8: 64px;
  --container: 1140px;
  --measure: 65ch;
  --gutter: 24px;
  --section-y: 78px;
  --section-y-lg: 109px;
}

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

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

body {
  margin: 0;
  padding-top: 60px;
  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);
  overflow-wrap: break-word;
  text-rendering: optimizeLegibility;
}

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

a { color: var(--color-accent); }

button { font: inherit; }

[hidden] { display: none !important; }

hr { border: 0; }

/* ---------- 中文排版与标题 ---------- */
h1, h2, h3, h4 {
  margin: 0 0 var(--space-2);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }

p { margin: 0 0 var(--space-2); }

ul, ol { margin: 0 0 var(--space-2); padding-left: 1.3em; }

strong { font-weight: 600; }

::selection {
  background: var(--color-primary-soft);
  color: var(--color-ink);
}

/* ---------- 布局 ---------- */
.wrap {
  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); }

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--gutter);
}

.col--wide { grid-column: 1 / -1; }

.col--narrow { grid-column: 1 / -1; }

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

.stack {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.flow > * + * { margin-top: var(--space-3); }

@media (min-width: 768px) {
  .col--wide { grid-column: 1 / span 8; }
  .col--narrow { grid-column: 10 / span 3; }
}

@media (min-width: 900px) {
  .spread { grid-template-columns: minmax(0, 8fr) minmax(0, 3fr); }
}

/* ---------- 文本组件 ---------- */
.display-title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.section-title {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.lede {
  font-size: var(--text-lg);
  line-height: 1.7;
  color: var(--color-ink-soft);
}

.prose {
  max-width: var(--measure);
  color: var(--color-ink);
}

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

.prose h2 {
  margin: var(--space-6) 0 var(--space-2);
  font-size: var(--text-2xl);
}

.prose h3 {
  margin: var(--space-4) 0 var(--space-1);
  font-size: var(--text-xl);
}

.marginalia {
  font-size: var(--text-sm);
  line-height: 1.75;
  color: var(--color-ink-soft);
}

.meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  color: var(--color-ink-muted);
}

.print-label {
  display: inline-block;
  padding: 4px 10px;
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-primary);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  line-height: 1.4;
}

.print-label--solid {
  background: var(--color-primary);
  color: var(--color-primary-ink);
}

.quote {
  margin: var(--space-4) 0;
  padding-left: var(--space-3);
  border-left: 2px solid var(--color-primary);
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink);
}

.rule-hair {
  border-top: 1px solid var(--color-line);
  margin: var(--space-4) 0;
}

.rule-double {
  position: relative;
  padding-top: var(--space-2);
}

.rule-double::before,
.rule-double::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-line);
}

.rule-double::before { top: 0; }
.rule-double::after { top: 3px; }

/* ---------- 标签与面包屑 ---------- */
.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

.tag {
  padding: 4px 10px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface-alt);
  color: var(--color-ink-soft);
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
}

.breadcrumb {
  margin-block: var(--space-3);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

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

.breadcrumb a {
  color: var(--color-ink-soft);
  text-decoration: none;
  border-bottom: 1px solid var(--color-line);
}

.breadcrumb a:hover {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 12px 20px;
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-primary);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
}

.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));
  color: var(--color-primary-ink);
}

.btn--ghost {
  border-color: var(--color-line);
  color: var(--color-ink-soft);
}

.btn--ghost:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-surface-alt);
}

/* ---------- 深色数据面板 ---------- */
.panel-dark {
  padding: var(--space-4);
  border: 1px solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.panel-dark__head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-contrast-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  color: var(--color-contrast-ink);
}

.data-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.data-num--figure {
  font-size: var(--text-figure);
  line-height: 1;
  color: var(--color-primary);
}

.panel-dark .data-num--figure { color: var(--color-contrast-accent); }

/* ---------- 时间轴 ---------- */
.timeline {
  position: relative;
  height: 56px;
  margin-block: var(--space-3);
}

.timeline__track {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 1px;
  background: var(--color-line);
}

.timeline__cursor {
  position: absolute;
  top: calc(50% - 12px);
  width: 2px;
  height: 24px;
  background: var(--color-accent);
}

.panel-dark .timeline__track { background: var(--color-contrast-line); }

.panel-dark .timeline__cursor { background: var(--color-contrast-accent); }

/* ---------- 口径切换 ---------- */
.tabs { margin-block: var(--space-4); }

.tablist {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  border-bottom: 1px solid var(--color-line);
}

.tab {
  appearance: none;
  padding: 10px 16px;
  border: 1px solid transparent;
  border-bottom: 0;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  background: transparent;
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  cursor: pointer;
}

.tab:hover { color: var(--color-primary); }

.tab[aria-selected="true"] {
  position: relative;
  top: 1px;
  background: var(--color-primary-soft);
  border-color: var(--color-line);
  color: var(--color-primary);
}

.tabpanel { padding-top: var(--space-3); }

.panel-dark .tablist { border-bottom-color: var(--color-contrast-line); }

.panel-dark .tab { color: var(--color-contrast-ink); }

.panel-dark .tab[aria-selected="true"] {
  background: color-mix(in srgb, var(--color-contrast-accent) 22%, var(--color-contrast-surface));
  border-color: var(--color-contrast-line);
  color: var(--color-contrast-ink);
}

/* ---------- 图片容器 ---------- */
.figure { margin: 0; }

.figure__media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface-deep);
}

.figure__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure--wide .figure__media { aspect-ratio: 16 / 9; }
.figure--tall .figure__media { aspect-ratio: 3 / 4; }
.figure--square .figure__media { aspect-ratio: 1 / 1; }
.figure--narrow .figure__media { aspect-ratio: 4 / 5; }

.figure__body {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: var(--space-3);
  background: var(--overlay-scrim);
  color: var(--color-contrast-ink);
}

.figure__caption {
  margin-top: var(--space-1);
  font-size: var(--text-xs);
  letter-spacing: 0.02em;
  color: var(--color-ink-soft);
}

/* ---------- 跳过链接 ---------- */
.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -80px;
  z-index: 200;
  padding: 10px 16px;
  border: 1px solid var(--color-primary);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  text-decoration: none;
  transition: top 0.2s ease;
}

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

/* ---------- 头部：侧边轨道导航 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 90;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  height: 60px;
  padding: 0 var(--space-2);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-line);
}

.header-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  height: 60px;
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 2px;
  text-decoration: none;
  color: var(--color-ink);
}

.brand__name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  letter-spacing: 0.04em;
  line-height: 1.1;
}

.brand__sub {
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  color: var(--color-ink-muted);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 8px 12px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-ink);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  cursor: pointer;
}

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

.nav-toggle__bars {
  position: relative;
  display: block;
  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;
}

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

.site-nav {
  position: fixed;
  top: 60px;
  left: 0;
  bottom: 0;
  z-index: 88;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  width: min(84vw, 320px);
  padding: var(--space-4) var(--space-3);
  overflow-y: auto;
  background: var(--color-surface-alt);
  border-right: 1px solid var(--color-line);
  transform: translateX(-101%);
  transition: transform 0.28s ease;
}

.site-header[data-open] .site-nav { transform: translateX(0); }

.site-nav__caption {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.24em;
  color: var(--color-ink-muted);
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-list__item { list-style: none; }

.nav-link {
  display: block;
  padding: 10px 12px;
  border-left: 2px solid transparent;
  color: var(--color-ink);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: color 0.2s ease, background-color 0.2s ease, border-color 0.2s ease;
}

.nav-link:hover {
  background: var(--color-primary-soft);
  color: var(--color-primary);
}

.nav-link[aria-current="page"] {
  border-left-color: var(--color-primary);
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-weight: 600;
}

.rail-status {
  display: flex;
  gap: var(--space-1);
  align-items: baseline;
  margin-top: auto;
  padding-top: var(--space-2);
  border-top: 1px solid var(--color-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
}

.rail-status__label {
  color: var(--color-primary);
  letter-spacing: 0.18em;
}

.rail-status__value {
  color: var(--color-ink);
  letter-spacing: 0.04em;
}

.nav-scrim {
  position: fixed;
  inset: 60px 0 0 0;
  z-index: 85;
  background: var(--overlay-scrim);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.28s ease;
}

.site-header[data-open] .nav-scrim {
  opacity: 1;
  pointer-events: auto;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 95;
  width: 0;
  height: 2px;
  background: var(--color-primary);
}

/* ---------- 页脚：大字收尾 ---------- */
.site-footer {
  padding-block: var(--section-y-lg) var(--space-4);
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  border-top: 1px solid var(--color-contrast-line);
}

.footer-top {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--space-3);
}

.footer-wordmark {
  margin: 0;
  font-family: var(--font-heading);
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: 0.95;
  letter-spacing: 0.02em;
  color: color-mix(in srgb, var(--color-primary) 72%, var(--color-contrast-ink));
}

.footer-top__side {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-2);
}

.footer-tagline {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.22em;
  color: color-mix(in srgb, var(--color-contrast-ink) 82%, var(--color-contrast-surface));
}

.to-top {
  padding: 10px 14px;
  border: 1px solid var(--color-contrast-line);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-contrast-ink);
  font-size: var(--text-xs);
  letter-spacing: 0.18em;
  cursor: pointer;
}

.to-top:hover {
  border-color: color-mix(in srgb, var(--color-primary) 70%, var(--color-contrast-ink));
  color: color-mix(in srgb, var(--color-primary) 60%, var(--color-contrast-ink));
}

.footer-cols {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-6);
  padding-top: var(--space-3);
}

.footer-cols::before,
.footer-cols::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--color-contrast-line);
}

.footer-cols::before { top: 0; }
.footer-cols::after { top: 3px; }

.footer-col__label {
  margin: 0 0 var(--space-2);
}

.site-footer .print-label {
  border-color: color-mix(in srgb, var(--color-primary) 68%, var(--color-contrast-ink));
  color: color-mix(in srgb, var(--color-primary) 58%, var(--color-contrast-ink));
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: var(--text-sm);
  color: var(--color-contrast-ink);
}

.footer-list a {
  color: var(--color-contrast-ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.footer-list a:hover {
  color: color-mix(in srgb, var(--color-primary) 58%, var(--color-contrast-ink));
  border-bottom-color: color-mix(in srgb, var(--color-primary) 70%, var(--color-contrast-ink));
}

.footer-list--plain { color: color-mix(in srgb, var(--color-contrast-ink) 86%, var(--color-contrast-surface)); }

.footer-legal {
  margin: var(--space-6) 0 0;
  padding-top: var(--space-2);
  border-top: 1px solid var(--color-contrast-line);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: color-mix(in srgb, var(--color-contrast-ink) 74%, var(--color-contrast-surface));
}

/* ---------- 动效 ---------- */
.js .reveal {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.4s ease, transform 0.4s ease;
}

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

/* ---------- 焦点 ---------- */
:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

.nav-link:focus-visible {
  outline-offset: -2px;
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 768px) {
  .footer-cols { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 1024px) {
  body {
    padding-top: 0;
    padding-left: 240px;
  }

  .site-header {
    right: auto;
    bottom: 0;
    width: 240px;
    height: auto;
    padding: var(--space-4) var(--space-3) var(--space-3);
    border-bottom: 0;
    border-right: 1px solid var(--color-line);
  }

  .header-top {
    height: auto;
    padding-bottom: var(--space-3);
    border-bottom: 1px solid var(--color-line);
  }

  .nav-toggle { display: none; }

  .site-nav {
    position: static;
    top: auto;
    bottom: auto;
    z-index: auto;
    width: auto;
    flex: 1;
    padding: 0;
    overflow: visible;
    background: transparent;
    border-right: 0;
    transform: none;
    transition: none;
  }

  .nav-scrim { display: none; }

  .site-header[data-open] .site-nav { transform: none; }

  .footer-wordmark { letter-spacing: 0.04em; }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .js .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .site-nav { transition: none; }

  .nav-scrim { transition: none; }
}