/* ==========================================================================
   安博赛场 — /assets/site.css
   共享外壳与基础组件：reset / 变量 / 中文排版 / 头部 / 页脚 / 通用组件
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. 变量
   -------------------------------------------------------------------------- */
:root {
  /* 色彩：草原夜空体系 */
  --night: #071A2E;
  --teal-deep: #06312F;
  --indigo: #221A45;
  --wine: #59182B;
  --lime: #55F2A0;
  --orange: #FF7A29;
  --silver: #C6D3DE;
  --cloud: #EEF4FA;
  --slate: #7E8FA3;
  --ink-deep: #04101F;
  --cyan: #37D6E0;

  /* 线条与描边 */
  --line: rgba(198, 211, 222, 0.16);
  --line-strong: rgba(198, 211, 222, 0.34);
  --line-lime: rgba(85, 242, 160, 0.42);
  --line-orange: rgba(255, 122, 41, 0.5);

  /* 字体 */
  --font-sans: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Segoe UI", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", "SFMono-Regular", Consolas, Menlo,
    "Liberation Mono", monospace;

  /* 字号阶梯 96 / 72 / 56 / 40 / 28 / 20 / 16 / 13 / 11 */
  --fs-96: 96px;
  --fs-72: 72px;
  --fs-56: 56px;
  --fs-40: 40px;
  --fs-28: 28px;
  --fs-20: 20px;
  --fs-16: 16px;
  --fs-13: 13px;
  --fs-11: 11px;

  /* 节奏 */
  --gutter: 64px;
  --page-max: 1320px;
  --gap: 24px;
  --block: 24px;
  --chapter: 96px;
  --dense-row: 40px;
  --card-min: 180px;

  /* 形状 */
  --clip-card: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 0 100%);
  --clip-card-lg: polygon(0 0, calc(100% - 28px) 0, 100% 28px, 100% 100%, 0 100%);
  --radius-pill: 999px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

@media (max-width: 1024px) {
  :root { --gutter: 40px; --chapter: 72px; }
}
@media (max-width: 640px) {
  :root { --gutter: 20px; --chapter: 56px; --gap: 16px; --block: 16px; }
}

/* --------------------------------------------------------------------------
   2. Reset
   -------------------------------------------------------------------------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--night);
  color: var(--cloud);
  font-family: var(--font-sans);
  font-size: var(--fs-16);
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }

a {
  color: var(--silver);
  text-decoration: none;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

a:active { filter: brightness(0.92); }

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

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

hr {
  border: 0;
  height: 1px;
  background: var(--line);
  margin: 0;
}

:focus { outline: none; }
:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 2px;
  border-radius: 2px;
}

::selection {
  background: var(--lime);
  color: var(--ink-deep);
}

/* --------------------------------------------------------------------------
   3. 中文排版与骨架
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--page-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  padding-block: 0;
  margin-bottom: var(--chapter);
}
.section--dense { margin-bottom: calc(var(--chapter) * 0.55); }
.section--tint-teal { background: var(--teal-deep); }
.section--tint-indigo { background: var(--indigo); }
.section--tint-wine { background: var(--wine); }

.hairline {
  height: 1px;
  background: var(--line);
  border: 0;
  margin-block: var(--block);
}

/* 左右分屏骨架 38 / 62 */
.split {
  display: grid;
  grid-template-columns: 38fr 62fr;
  gap: var(--gap);
  align-items: start;
}
.split__aside { min-width: 0; }
.split__main { min-width: 0; }

@media (min-width: 1440px) {
  .split { grid-template-columns: 34fr 66fr; }
}
@media (max-width: 1024px) {
  .split { grid-template-columns: 46fr 54fr; }
}
@media (max-width: 760px) {
  .split { grid-template-columns: 1fr; }
}

/* 超大排版 */
.display {
  font-family: var(--font-sans);
  font-weight: 200;
  line-height: 1.02;
  letter-spacing: -0.02em;
  color: var(--cloud);
  text-wrap: balance;
}
.display--xl { font-size: var(--fs-96); }
.display--lg { font-size: var(--fs-72); }
.display--md { font-size: var(--fs-56); }

@media (max-width: 900px) {
  .display--xl { font-size: var(--fs-56); }
  .display--lg { font-size: var(--fs-40); }
  .display--md { font-size: var(--fs-40); }
}
@media (max-width: 560px) {
  .display--xl { font-size: var(--fs-40); }
}

.page-head { padding-block: 24px 48px; }

/* 小索引行 */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-11);
  font-weight: 600;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--slate);
  margin-bottom: 16px;
}
.eyebrow--cn {
  font-family: var(--font-sans);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: none;
}
.eyebrow::before {
  content: "";
  width: 18px;
  height: 1px;
  background: var(--lime);
  flex: none;
}

/* 正文 */
.prose {
  max-width: 72ch;
  color: var(--cloud);
  font-size: var(--fs-16);
  line-height: 1.75;
}
.prose--wide { max-width: 76ch; }
.prose p + p { margin-top: 28px; }
.prose strong { font-weight: 700; color: var(--cloud); }
.prose a { color: var(--silver); }
.prose a:hover { color: var(--lime); }

/* 面包屑 */
.breadcrumb { margin-bottom: 24px; }
.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: var(--fs-13);
  color: var(--slate);
}
.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: var(--slate);
  opacity: 0.6;
}
.breadcrumb__link {
  color: var(--slate);
  transition: color 160ms var(--ease);
}
.breadcrumb__link:hover { color: var(--lime); }
.breadcrumb__item[aria-current="page"] { color: var(--silver); }

/* --------------------------------------------------------------------------
   4. 通用链接与按钮
   -------------------------------------------------------------------------- */
.link-inline {
  position: relative;
  display: inline-block;
  color: var(--silver);
  padding-left: 0;
  transition: color 160ms var(--ease), padding-left 160ms var(--ease);
}
.link-inline::before {
  content: "";
  position: absolute;
  left: -12px;
  top: calc(0.72em - 1px);
  width: 6px;
  height: 1px;
  background: var(--lime);
  opacity: 0;
  transition: opacity 160ms var(--ease), left 160ms var(--ease);
}
.link-inline:hover {
  color: var(--lime);
  padding-left: 12px;
}
.link-inline:hover::before { opacity: 1; left: 0; }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--silver);
  font-size: var(--fs-13);
  letter-spacing: 0.04em;
}
.link-arrow::after {
  content: "→";
  font-family: var(--font-mono);
  transition: transform 160ms var(--ease), color 160ms var(--ease);
}
.link-arrow:hover { color: var(--lime); }
.link-arrow:hover::after { transform: translateX(4px); }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 38px;
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  font-size: var(--fs-13);
  font-weight: 500;
  letter-spacing: 0.06em;
  white-space: nowrap;
  border: 1px solid transparent;
  transition: background 160ms var(--ease), border-color 160ms var(--ease),
    color 160ms var(--ease), transform 160ms var(--ease);
}
.btn--primary {
  background: var(--orange);
  color: var(--ink-deep);
  font-weight: 700;
}
.btn--primary:hover {
  background: #ff9350;
  color: var(--ink-deep);
}
.btn--ghost {
  border-color: var(--line-strong);
  color: var(--silver);
}
.btn--ghost:hover {
  border-color: var(--line-lime);
  color: var(--lime);
}
.btn--quiet {
  color: var(--slate);
  padding-inline: 8px;
}
.btn--quiet:hover { color: var(--lime); }

/* --------------------------------------------------------------------------
   5. 头部：悬浮胶囊导航
   -------------------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  display: flex;
  justify-content: center;
  padding: 18px var(--gutter) 0;
  pointer-events: none;
}

.skip-link {
  position: absolute;
  left: var(--gutter);
  top: 8px;
  transform: translateY(-160%);
  z-index: 100;
  padding: 10px 18px;
  background: var(--orange);
  color: var(--ink-deep);
  font-size: var(--fs-13);
  font-weight: 700;
  border-radius: var(--radius-pill);
  pointer-events: auto;
  transition: transform 160ms var(--ease);
}
.skip-link:focus { transform: translateY(0); }

.nav-shell {
  pointer-events: auto;
  position: relative;
  width: 100%;
  max-width: var(--page-max);
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 9px 10px 9px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(7, 26, 46, 0.72);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: max-width 220ms var(--ease), background 220ms var(--ease),
    border-color 220ms var(--ease), padding 220ms var(--ease);
}

/* 滚动收窄 */
.site-header[data-condensed="true"] .nav-shell {
  max-width: 1080px;
  padding-block: 6px;
  background: rgba(4, 16, 31, 0.9);
  border-color: rgba(198, 211, 222, 0.1);
}
.site-header[data-condensed="true"] .brand__sub {
  opacity: 0;
  visibility: hidden;
}

.brand {
  display: flex;
  flex-direction: column;
  gap: 2px;
  order: 0;
  flex: none;
  line-height: 1.2;
}
.brand__mark {
  font-size: var(--fs-20);
  font-weight: 300;
  letter-spacing: 0.14em;
  color: var(--cloud);
  transition: color 160ms var(--ease);
}
.brand:hover .brand__mark { color: var(--lime); }
.brand__sub {
  font-size: var(--fs-11);
  letter-spacing: 0.2em;
  color: var(--slate);
  transition: opacity 180ms var(--ease), visibility 180ms var(--ease);
}

.nav-toggle {
  order: 1;
  display: none;
  align-items: center;
  gap: 8px;
  min-height: 36px;
  padding: 8px 14px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  font-size: var(--fs-13);
  color: var(--silver);
  letter-spacing: 0.08em;
}
.nav-toggle__bars {
  position: relative;
  width: 14px;
  height: 8px;
  flex: none;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 1px;
  background: currentColor;
  transition: transform 160ms var(--ease), top 160ms var(--ease);
}
.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { top: 7px; }
.nav-toggle[aria-expanded="true"] { color: var(--orange); border-color: var(--line-orange); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { top: 4px; transform: rotate(35deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { top: 4px; transform: rotate(-35deg); }

.site-nav {
  order: 2;
  flex: 1;
  display: flex;
  align-items: center;
  gap: 16px;
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  margin-inline: auto;
  flex-wrap: nowrap;
}
.nav-list__item { display: flex; }
.nav-list__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 12px;
  border-radius: var(--radius-pill);
  font-size: var(--fs-13);
  color: var(--slate);
  white-space: nowrap;
  transition: color 160ms var(--ease), background 160ms var(--ease);
}
.nav-list__link::before {
  content: "";
  width: 5px;
  height: 5px;
  flex: none;
  border-radius: 50%;
  background: var(--orange);
  opacity: 0;
  transform: scale(0.6);
  transition: opacity 160ms var(--ease), transform 160ms var(--ease);
}
.nav-list__link:hover {
  color: var(--cloud);
  background: rgba(198, 211, 222, 0.07);
}
.nav-list__link[aria-current="page"] {
  color: var(--cloud);
  background: rgba(85, 242, 160, 0.08);
}
.nav-list__link[aria-current="page"]::before {
  opacity: 1;
  transform: none;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: none;
}

.scroll-progress {
  position: fixed;
  left: 0;
  top: 0;
  width: 100%;
  height: 2px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--lime) 0%, var(--cyan) 60%, var(--orange) 100%);
  z-index: 90;
  pointer-events: none;
}

/* 手机 / 平板：胶囊收为单枚按钮，导航纵向展开 */
@media (max-width: 1100px) {
  .nav-list__link { padding-inline: 9px; }
}
@media (max-width: 980px) {
  .site-header { padding-top: 12px; }
  .nav-shell {
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    border-radius: 22px;
    padding: 8px 10px 8px 16px;
    row-gap: 0;
  }
  .site-header[data-condensed="true"] .nav-shell { border-radius: 22px; }
  .nav-toggle { display: inline-flex; }
  .site-nav {
    order: 3;
    flex-basis: 100%;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px 0 6px;
    border-top: 1px solid var(--line);
    margin-top: 8px;
  }
  .nav-shell[data-open="true"] .site-nav { display: flex; }
  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin-inline: 0;
  }
  .nav-list__link {
    padding: 11px 4px;
    border-radius: 8px;
    font-size: var(--fs-16);
    color: var(--silver);
  }
  .nav-actions {
    flex-direction: column;
    align-items: stretch;
    margin-top: 12px;
    gap: 8px;
  }
  .nav-actions .btn { min-height: 44px; }
}

/* --------------------------------------------------------------------------
   6. 页脚
   -------------------------------------------------------------------------- */
.site-footer {
  margin-top: var(--chapter);
  background: var(--ink-deep);
  border-top: 1px solid var(--line);
  color: var(--silver);
  font-size: var(--fs-13);
}

.footer-inner {
  width: 100%;
  max-width: var(--page-max);
  margin-inline: auto;
  padding: 64px var(--gutter) 48px;
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: 48px;
  align-items: start;
}

.footer-lead { max-width: 34ch; }
.footer-brand {
  font-size: var(--fs-28);
  font-weight: 300;
  letter-spacing: 0.1em;
  color: var(--cloud);
  line-height: 1.2;
}
.footer-brand::after {
  content: "";
  display: block;
  width: 36px;
  height: 2px;
  margin-top: 16px;
  background: var(--lime);
}
.footer-intro {
  margin-top: 20px;
  color: var(--slate);
  line-height: 1.75;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}
.footer-col__heading {
  font-family: var(--font-mono);
  font-size: var(--fs-11);
  font-weight: 600;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--slate);
  margin-bottom: 16px;
}
.footer-col__list { display: flex; flex-direction: column; gap: 2px; }
.footer-col__link {
  position: relative;
  display: inline-block;
  padding-block: 7px;
  padding-left: 0;
  color: var(--silver);
  transition: color 160ms var(--ease), padding-left 160ms var(--ease);
}
.footer-col__link::before {
  content: "";
  position: absolute;
  left: -12px;
  top: calc(50% - 1px);
  width: 6px;
  height: 1px;
  background: var(--lime);
  opacity: 0;
  transition: opacity 160ms var(--ease), left 160ms var(--ease);
}
.footer-col__link:hover {
  color: var(--lime);
  padding-left: 12px;
}
.footer-col__link:hover::before { opacity: 1; left: 0; }

.footer-base {
  width: 100%;
  max-width: var(--page-max);
  margin-inline: auto;
  padding: 24px var(--gutter) 40px;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 8px 32px;
  color: var(--slate);
  font-size: var(--fs-13);
  line-height: 1.9;
}
.footer-contact { color: var(--silver); font-family: var(--font-mono); font-size: 12px; }
.footer-address { color: var(--slate); }
.footer-note { color: var(--slate); }
.footer-legal { color: var(--slate); font-family: var(--font-mono); font-size: 12px; }
.footer-copy { color: var(--slate); font-family: var(--font-mono); font-size: 12px; }

@media (max-width: 900px) {
  .footer-inner {
    grid-template-columns: 1fr;
    gap: 40px;
    padding-top: 48px;
  }
  .footer-lead { max-width: 46ch; }
}
@media (max-width: 640px) {
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-inner { padding-bottom: 32px; }
}

/* --------------------------------------------------------------------------
   7. 面板 / 指标 / 标签 / 卡片
   -------------------------------------------------------------------------- */
.panel {
  position: relative;
  padding: var(--block);
  background: var(--night);
  border: 1px solid var(--line);
  clip-path: var(--clip-card);
  transition: border-color 180ms var(--ease), background 180ms var(--ease);
}
.panel--data { background: var(--teal-deep); }
.panel--archive {
  background: var(--indigo);
  clip-path: var(--clip-card-lg);
  padding: calc(var(--block) * 1.5);
}
.panel--wine { background: var(--wine); }
.panel:hover { border-color: var(--line-lime); }

.metric {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-height: var(--card-min);
  justify-content: flex-end;
}
.metric__value {
  font-family: var(--font-mono);
  font-size: var(--fs-72);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--lime);
}
.metric__value--orange { color: var(--orange); }
.metric__value--cyan { color: var(--cyan); }
.metric__label {
  font-size: var(--fs-13);
  color: var(--slate);
  letter-spacing: 0.06em;
}
.metric__delta {
  font-family: var(--font-mono);
  font-size: var(--fs-11);
  letter-spacing: 0.16em;
  color: var(--silver);
}

@media (max-width: 900px) {
  .metric__value { font-size: var(--fs-40); }
}

.data-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  font-size: var(--fs-11);
  letter-spacing: 0.16em;
  color: var(--silver);
  white-space: nowrap;
}
.tag--lime { color: var(--lime); border-color: var(--line-lime); }
.tag--orange { color: var(--orange); border-color: var(--line-orange); }
.tag--wine { color: #f0a9bd; border-color: rgba(240, 169, 189, 0.36); }

/* 错落卡片组：垂直错位 24px / 48px */
.card-stagger {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--gap);
  align-items: start;
}
.card-stagger__item:nth-child(2n) { transform: translateY(24px); }
.card-stagger__item:nth-child(3n) { transform: translateY(48px); }
@media (max-width: 760px) {
  .card-stagger__item:nth-child(2n),
  .card-stagger__item:nth-child(3n) { transform: none; }
}

/* 右侧索引轨迹线 */
.index-rail {
  position: fixed;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 60;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 12px 6px;
}
.index-rail::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  background: var(--line);
}
.index-rail__node {
  position: relative;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  border: 1px solid var(--silver);
  background: var(--night);
  transition: background 180ms var(--ease), border-color 180ms var(--ease),
    transform 180ms var(--ease);
}
.index-rail__node:hover {
  border-color: var(--lime);
  transform: scale(1.2);
}
.index-rail__node[aria-current="true"] {
  background: var(--lime);
  border-color: var(--lime);
  transform: scale(1.2);
}
@media (max-width: 1100px) {
  .index-rail { display: none; }
}

/* --------------------------------------------------------------------------
   8. 筛选条 / 轮次时间轴 / 折叠面板
   -------------------------------------------------------------------------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 12px 0;
  border-block: 1px solid var(--line);
}
.filter-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  font-size: var(--fs-13);
  color: var(--silver);
  transition: border-color 160ms var(--ease), color 160ms var(--ease),
    background 160ms var(--ease);
}
.filter-chip:hover { border-color: var(--line-lime); color: var(--lime); }
.filter-chip[aria-pressed="true"] {
  background: var(--orange);
  border-color: var(--orange);
  color: var(--ink-deep);
  font-weight: 700;
}

.round-timeline {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding-block: 8px;
  scrollbar-width: thin;
  scrollbar-color: var(--silver) transparent;
}
.round-timeline__item {
  scroll-snap-align: center;
  flex: none;
  min-width: 96px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-top: 2px solid var(--silver);
  background: rgba(198, 211, 222, 0.04);
  font-family: var(--font-mono);
  font-size: var(--fs-13);
  color: var(--silver);
  transition: border-color 160ms var(--ease), color 160ms var(--ease),
    transform 160ms var(--ease), background 160ms var(--ease);
}
.round-timeline__item:hover { border-color: var(--line-lime); color: var(--lime); }
.round-timeline__item[aria-current="true"] {
  transform: scale(1.15);
  border-color: var(--lime);
  border-top-color: var(--lime);
  color: var(--lime);
  background: rgba(85, 242, 160, 0.09);
}
.round-timeline::-webkit-scrollbar { height: 6px; }
.round-timeline::-webkit-scrollbar-thumb { background: var(--line-strong); }

.fold-panel {
  border: 1px solid var(--line);
  background: var(--teal-deep);
  clip-path: var(--clip-card);
}
.fold-panel__summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px var(--block);
  cursor: pointer;
  font-size: var(--fs-16);
  color: var(--cloud);
  list-style: none;
}
.fold-panel__summary::-webkit-details-marker { display: none; }
.fold-panel__summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: var(--fs-20);
  color: var(--lime);
  transition: transform 180ms var(--ease);
}
.fold-panel[open] .fold-panel__summary::after { transform: rotate(45deg); }
.fold-panel__body {
  padding: 0 var(--block) var(--block);
  color: var(--silver);
  font-size: var(--fs-13);
  line-height: 1.8;
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

/* --------------------------------------------------------------------------
   9. 图片容器（页面阶段放置占位图）
   -------------------------------------------------------------------------- */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: linear-gradient(135deg, var(--teal-deep) 0%, var(--indigo) 100%);
  border: 1px solid var(--line);
  aspect-ratio: 16 / 9;
}
.media-frame > img,
.media-frame > picture > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 28px 16px 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-11);
  letter-spacing: 0.12em;
  color: var(--silver);
  background: linear-gradient(to top, rgba(4, 16, 31, 0.94), rgba(4, 16, 31, 0));
}

/* --------------------------------------------------------------------------
   10. 滚动显现
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: no-preference) {
  [data-reveal] {
    opacity: 0;
    transform: translateY(12px);
    transition: opacity 420ms var(--ease), transform 420ms var(--ease);
  }
  [data-reveal].is-revealed {
    opacity: 1;
    transform: none;
  }
}

/* --------------------------------------------------------------------------
   11. 无障碍：减弱动效
   -------------------------------------------------------------------------- */
@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;
    scroll-behavior: auto !important;
  }
  .scroll-progress { display: none; }
  [data-reveal] { opacity: 1 !important; transform: none !important; }
  .round-timeline__item[aria-current="true"] { transform: none; }
  .index-rail__node:hover { transform: none; }
}