:root {
  --color-surface: #fafafb;
  --color-surface-alt: #f0f0f1;
  --color-surface-deep: #e2e2e3;
  --color-ink: #2f3137;
  --color-ink-soft: #5c606b;
  --color-ink-muted: #777c88;
  --color-line: #d5d6d8;
  --color-primary: #0c4ff3;
  --color-primary-ink: #ffffff;
  --color-primary-soft: #d9e2fa;
  --color-accent: #ea005d;
  --color-accent-ink: #ffffff;
  --color-highlight: #f7cddf;
  --color-focus: #e00059;
  --color-contrast-surface: #111828;
  --color-contrast-ink: #e4e5e7;
  --color-contrast-line: #3f4552;
  --color-contrast-accent: #ff0065;
  --overlay-scrim: linear-gradient(180deg, rgba(17, 24, 40, 0.35) 0%, rgba(17, 24, 40, 0.72) 55%, rgba(17, 24, 40, 0.92) 100%);
  --font-heading: "Source Han Sans SC", "Noto Sans SC", SimHei, "Microsoft YaHei", sans-serif;
  --font-body: "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-mono: ui-monospace, Menlo, Consolas, monospace;
  --text-xs: 10.4px;
  --text-sm: 13.9px;
  --text-base: 16px;
  --text-lg: 21.3px;
  --text-xl: 28.4px;
  --text-2xl: 37.9px;
  --text-3xl: 50.5px;
  --text-4xl: 67.3px;
  --text-display: clamp(42px, 8.6vw, 110px);
  --text-figure: clamp(35px, 6.2vw, 79px);
  --weight-heading: 855;
  --weight-body: 400;
  --leading-body: 1.72;
  --leading-heading: 1.21;
  --tracking-heading: -0.014em;
  --radius-sm: 88px;
  --radius-md: 308px;
  --radius-lg: 528px;
  --radius-pill: 999px;
  --border-thin: 2px;
  --border-thick: 3px;
  --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: 1180px;
  --measure: 66ch;
  --gutter: 16px;
  --section-y: 82px;
  --section-y-lg: 115px;
}

/* 派生尺寸（仅结构长度，不改动色板与字号定稿） */
:root {
  --rail-w: 236px;
}

/* ============ 基础重置 ============ */
*,
*::before,
*::after { box-sizing: border-box; }

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

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);
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
}

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);
  text-wrap: balance;
}

h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }
h5, h6 { font-size: var(--text-base); }

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

figure { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
table { border-collapse: collapse; }

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 180ms ease, border-color 180ms ease, background-color 180ms ease;
}
a:hover { color: var(--color-accent); }

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

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

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

/* ============ 布局工具 ============ */
.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--band { background-color: var(--color-surface-alt); }
.section--soft { background-color: var(--color-primary-soft); }

.section--dark {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.section--dark h1,
.section--dark h2,
.section--dark h3,
.section--dark h4,
.section--dark p { color: var(--color-contrast-ink); }
.section--dark a { color: var(--color-contrast-accent); }

.section--primary {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.section--primary h1,
.section--primary h2,
.section--primary h3,
.section--primary p { color: var(--color-primary-ink); }
.section--primary a { color: var(--color-primary-ink); }

.grid {
  display: grid;
  gap: var(--gutter);
  grid-template-columns: repeat(8, minmax(0, 1fr));
}
.span-1, .span-2, .span-3, .span-4, .span-5, .span-6, .span-7, .span-8 {
  grid-column: 1 / -1;
}
.span-1 { grid-column: span 1; }
.span-2 { grid-column: span 1; }
.span-3 { grid-column: span 1; }
.span-4 { grid-column: span 1; }
.span-5 { grid-column: span 1; }
.span-6 { grid-column: span 1; }
.span-7 { grid-column: span 1; }
.span-8 { grid-column: 1 / -1; }

/* ============ 排版块 ============ */
.prose {
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  overflow-wrap: break-word;
}
.prose > * + * { margin-top: var(--space-3); }
.prose h2 { margin-top: var(--space-6); font-size: var(--text-2xl); }
.prose h3 { margin-top: var(--space-4); font-size: var(--text-xl); }
.prose h4 { margin-top: var(--space-4); font-size: var(--text-lg); }
.prose ul { display: flex; flex-direction: column; gap: var(--space-1); }
.prose ul li { position: relative; padding-left: var(--space-3); }
.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 8px;
  height: 8px;
  border-radius: var(--radius-pill);
  background-color: var(--color-accent);
}
.prose a {
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 40%, transparent);
}
.prose a:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}
.prose__lead {
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink-soft);
  max-width: var(--measure);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  margin-bottom: var(--space-2);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.eyebrow::before {
  content: "";
  width: 28px;
  height: var(--border-thick);
  background-color: var(--color-accent);
}

.spec-label {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.label-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 6px var(--space-3);
  background-color: var(--color-highlight);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  border-radius: var(--radius-pill);
  transition: background-color 180ms ease, color 180ms ease, letter-spacing 180ms ease;
}
.label-tag:hover {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
  letter-spacing: 0.2em;
}
.label-tag.is-active,
.label-tag[aria-pressed="true"] {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  line-height: 1.2;
  letter-spacing: 0.02em;
  text-align: center;
  border: var(--border-thin) solid transparent;
  border-radius: 0;
  transition: background-color 180ms ease, color 180ms ease, border-color 180ms ease;
}
.btn--primary {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.btn--primary:hover {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn--accent {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.btn--accent:hover {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.btn--ghost {
  background-color: transparent;
  color: var(--color-ink);
  border-color: var(--color-ink);
}
.btn--ghost:hover {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.btn--onDark {
  background-color: transparent;
  color: var(--color-contrast-ink);
  border-color: var(--color-contrast-ink);
}
.btn--onDark:hover {
  background-color: var(--color-contrast-accent);
  border-color: var(--color-contrast-accent);
  color: var(--color-contrast-ink);
}
.btn--pill { border-radius: var(--radius-pill); }

/* ============ 面包屑 ============ */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1);
  margin-bottom: var(--space-3);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}
.crumbs a { color: var(--color-ink-soft); }
.crumbs a:hover { color: var(--color-accent); }
.crumbs__sep { color: var(--color-ink-muted); }

/* ============ 面板 ============ */
.panel {
  padding: var(--space-6);
  background-color: var(--color-surface-alt);
  color: var(--color-ink);
}
.panel h2, .panel h3, .panel h4 { color: inherit; }
.panel p:last-child { margin-bottom: 0; }
.panel--soft { background-color: var(--color-primary-soft); }
.panel--primary {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.panel--primary a { color: var(--color-primary-ink); }
.panel--accent {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.panel--accent a { color: var(--color-accent-ink); }
.panel--dark {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.panel--dark a { color: var(--color-contrast-accent); }

/* ============ 刻度数据 ============ */
.figures {
  display: grid;
  gap: var(--space-4);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.figure-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding-top: var(--space-3);
  border-top: var(--border-thick) solid var(--color-line);
}
.figure-item__num {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-figure);
  line-height: 0.95;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--color-accent);
}
.figure-item__label {
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}
.section--dark .figure-item__num { color: var(--color-contrast-accent); }
.section--dark .figure-item__label { color: var(--color-contrast-ink); }
.section--dark .figure-item { border-top-color: var(--color-contrast-line); }

/* ============ 图片容器 ============ */
.fig {
  position: relative;
  margin: 0;
  overflow: hidden;
  background-color: var(--color-surface-deep);
  isolation: isolate;
}
.fig__media {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.fig--wide { aspect-ratio: 16 / 9; }
.fig--land { aspect-ratio: 3 / 2; }
.fig--tall { aspect-ratio: 3 / 4; }
.fig--slim { aspect-ratio: 1 / 2; }
.fig--square { aspect-ratio: 1 / 1; }
.fig--circle {
  aspect-ratio: 1 / 1;
  border-radius: var(--radius-lg);
}
.fig--arch { border-radius: var(--radius-pill) var(--radius-pill) 0 0; }

.fig__scrim {
  position: absolute;
  inset: 0;
  background: var(--overlay-scrim);
}
.fig__text {
  position: absolute;
  left: var(--space-4);
  right: var(--space-4);
  bottom: var(--space-4);
  color: var(--color-primary-ink);
}
.fig__text h2,
.fig__text h3,
.fig__text p {
  color: var(--color-primary-ink);
  margin-bottom: var(--space-1);
}
.fig__label {
  position: absolute;
  top: var(--space-3);
  left: var(--space-3);
  padding: 4px var(--space-2);
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
}
.fig__caption {
  margin-top: var(--space-1);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-ink-muted);
}

/* ============ 表格 ============ */
.data-table {
  width: 100%;
  font-size: var(--text-sm);
  color: var(--color-ink);
}
.data-table caption {
  padding-bottom: var(--space-2);
  text-align: left;
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-muted);
}
.data-table th,
.data-table td { padding: var(--space-2) var(--space-3); text-align: left; }
.data-table thead th {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-soft);
  border-bottom: var(--border-thick) solid var(--color-line);
}
.data-table tbody tr:nth-child(even) { background-color: var(--color-surface-alt); }
.data-table tbody td {
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-line) 55%, transparent);
}
.data-table .num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  text-align: right;
}
.data-table .is-flag {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  color: var(--color-accent);
}

/* ============ 头部 ============ */
.site-header {
  position: relative;
  z-index: 80;
}

.skip-link {
  position: absolute;
  left: var(--space-2);
  top: -160px;
  z-index: 200;
  padding: var(--space-2) var(--space-4);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.12em;
  transition: top 180ms ease;
}
.skip-link:focus {
  top: var(--space-2);
  color: var(--color-contrast-ink);
}

.header-top { background-color: var(--color-surface); }

.header-top__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-3);
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-3) var(--gutter);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-ink);
}
.brand:hover { color: var(--color-ink); }

.brand__mark {
  position: relative;
  flex: none;
  width: 40px;
  height: 40px;
  overflow: hidden;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary);
}
.brand__mark::before {
  content: "";
  position: absolute;
  inset: 0 0 0 50%;
  background-color: var(--color-accent);
}
.brand__mark::after {
  content: "";
  position: absolute;
  inset: 27%;
  border-radius: var(--radius-pill);
  background-color: var(--color-surface);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}
.brand__name {
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}
.brand__sub {
  font-size: var(--text-xs);
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.device-notice {
  order: 3;
  flex: 1 1 100%;
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
  color: var(--color-ink-soft);
}
.device-notice__dot {
  flex: none;
  width: 10px;
  height: 10px;
  border-radius: var(--radius-pill);
  background-color: var(--color-accent);
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  order: 2;
  margin-left: auto;
  padding: var(--space-2) var(--space-3);
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.12em;
  border-radius: var(--radius-pill);
  transition: background-color 180ms ease, color 180ms ease;
}
.nav-toggle:hover { background-color: var(--color-primary); color: var(--color-primary-ink); }
.nav-toggle[aria-expanded="true"] {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.nav-toggle__bars {
  display: inline-flex;
  flex-direction: column;
  gap: 4px;
  width: 18px;
}
.nav-toggle__bars span {
  display: block;
  height: var(--border-thin);
  background-color: currentColor;
}
.nav-toggle__bars span:nth-child(3) { width: 60%; }
.nav-toggle__label { line-height: 1; }

.site-nav {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  overflow: hidden;
  max-height: 0;
  transition: max-height 220ms ease;
}
.site-nav[data-open] {
  max-height: 72vh;
  overflow-y: auto;
}
.site-nav__kicker {
  margin: 0;
  padding: var(--space-3) var(--space-4) var(--space-1);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--color-contrast-accent);
}
.site-nav__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: 0 var(--space-2) var(--space-3);
}
.site-nav__link {
  display: block;
  padding: var(--space-2) var(--space-3);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  letter-spacing: var(--tracking-heading);
  border-radius: var(--radius-pill);
  transition: background-color 180ms ease, color 180ms ease, padding-left 180ms ease;
}
.site-nav__link:hover,
.site-nav__link:focus-visible {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
  padding-left: calc(var(--space-3) + var(--space-1));
}
.site-nav__link[aria-current="page"] {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.site-nav__arc { display: none; }

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--border-thick);
  z-index: 120;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
  pointer-events: none;
}

/* ============ 页脚 ============ */
.site-footer { background-color: var(--color-surface); }

.footer-step { padding-block: var(--section-y); }
.footer-step--index { background-color: var(--color-surface); }
.footer-step--direct {
  background-color: var(--color-surface-alt);
  padding-block: var(--space-8);
}
.footer-step--legal {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
  padding-block: var(--space-6);
}

.footer-index {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}
.footer-brand__name {
  margin: var(--space-3) 0 var(--space-1);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xl);
  letter-spacing: var(--tracking-heading);
}
.footer-brand__note {
  margin: 0;
  font-size: var(--text-sm);
  letter-spacing: 0.04em;
  color: var(--color-ink-muted);
}

.footer-heading {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-xs);
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.footer-nav__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.footer-nav__list a {
  display: inline-block;
  padding: 4px 0;
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  letter-spacing: 0.01em;
}
.footer-nav__list a:hover { color: var(--color-primary); }

.footer-paths__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.footer-paths__list a {
  display: block;
  padding: var(--space-2) var(--space-3);
  background-color: var(--color-primary-soft);
  color: var(--color-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-base);
  transition: background-color 180ms ease, color 180ms ease;
}
.footer-paths__list a:hover {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}

.footer-direct {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: 1fr;
}
.direct-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  min-height: 168px;
  padding: var(--space-4);
  overflow: hidden;
  isolation: isolate;
}
.direct-card::after {
  content: "";
  position: absolute;
  right: -48px;
  bottom: -48px;
  width: 128px;
  height: 128px;
  border-radius: var(--radius-pill);
  transition: transform 220ms ease;
}
.direct-card:hover::after { transform: scale(1.18); }
.direct-card--blue {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}
.direct-card--blue::after {
  background-color: color-mix(in srgb, var(--color-primary-ink) 24%, transparent);
}
.direct-card--red {
  background-color: var(--color-accent);
  color: var(--color-accent-ink);
}
.direct-card--red::after {
  background-color: color-mix(in srgb, var(--color-accent-ink) 24%, transparent);
}
.direct-card--dark {
  background-color: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}
.direct-card--dark::after {
  background-color: color-mix(in srgb, var(--color-contrast-accent) 26%, transparent);
}
.direct-card__kicker {
  font-size: var(--text-xs);
  letter-spacing: 0.34em;
  text-transform: uppercase;
  opacity: 0.86;
}
.direct-card__title {
  margin-top: auto;
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-lg);
  line-height: 1.25;
  letter-spacing: var(--tracking-heading);
}
.direct-card__arrow {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
}
.direct-card:hover { color: inherit; }

.footer-legal {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.footer-legal__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-2) var(--space-6);
}
.footer-legal__icp {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: 0.06em;
  color: var(--color-contrast-ink);
}
.footer-legal__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}
.footer-legal__links a {
  color: var(--color-contrast-ink);
  font-size: var(--text-sm);
  border-bottom: var(--border-thin) solid transparent;
}
.footer-legal__links a:hover {
  color: var(--color-contrast-accent);
  border-bottom-color: var(--color-contrast-accent);
}
.footer-legal__contact,
.footer-legal__address,
.footer-legal__note {
  margin: 0;
  font-size: var(--text-sm);
  color: color-mix(in srgb, var(--color-contrast-ink) 78%, transparent);
}
.footer-legal .mono { color: var(--color-contrast-ink); }

/* ============ 浮动快捷入口 ============ */
.quick-rail {
  position: fixed;
  right: var(--space-4);
  bottom: var(--space-4);
  z-index: 110;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: var(--space-1);
  background-color: var(--color-contrast-surface);
  border-radius: var(--radius-sm);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 200ms ease, transform 200ms ease, visibility 0s linear 200ms;
}
.quick-rail[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: none;
  transition-delay: 0s;
}
.quick-rail__item {
  display: block;
  padding: var(--space-2) var(--space-3);
  color: var(--color-contrast-ink);
  font-family: var(--font-heading);
  font-weight: var(--weight-heading);
  font-size: var(--text-sm);
  letter-spacing: 0.08em;
  white-space: nowrap;
  border-radius: var(--radius-pill);
  transition: background-color 180ms ease, color 180ms ease;
}
.quick-rail__item:hover {
  background-color: var(--color-primary);
  color: var(--color-primary-ink);
}

/* ============ 滚动显现 ============ */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 520ms ease, transform 520ms ease;
}
.js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ============ 响应式 ============ */
@media (max-width: 719px) {
  .site-nav__list {
    flex-direction: row;
    gap: var(--space-1);
    padding: 0 var(--space-3) var(--space-3);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  .site-nav__list::-webkit-scrollbar { display: none; }
  .site-nav__link {
    white-space: nowrap;
    font-size: var(--text-base);
  }
  .site-nav__link:hover,
  .site-nav__link:focus-visible { padding-left: var(--space-3); }
  .header-top__inner { padding-block: var(--space-2); }
}

@media (min-width: 640px) {
  .grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .span-1 { grid-column: span 1; }
  .span-2 { grid-column: span 2; }
  .span-3 { grid-column: span 2; }
  .span-4 { grid-column: span 4; }
  .span-5 { grid-column: span 4; }
  .span-6 { grid-column: span 4; }
  .span-7 { grid-column: span 4; }
  .span-8 { grid-column: 1 / -1; }
  .figures { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .footer-index { grid-template-columns: 1.4fr 1fr 1fr; }
  .footer-direct { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .device-notice { font-size: var(--text-sm); letter-spacing: 0.08em; }
}

@media (min-width: 768px) {
  .container { padding-inline: var(--space-3); }
}

@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }

  .container { padding-inline: var(--space-4); }

  .header-top__inner { padding-block: var(--space-4); }

  .device-notice {
    order: 0;
    flex: 0 1 auto;
    margin-left: auto;
  }
  .nav-toggle { display: none; }

  .site-nav {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: var(--rail-w);
    max-height: none;
    overflow: visible;
    display: flex;
    flex-direction: column;
    padding: var(--space-6) 0 var(--space-4);
    z-index: 90;
  }
  .site-nav__kicker {
    padding: var(--space-3) var(--space-4) var(--space-2);
  }
  .site-nav__list {
    flex-direction: column;
    gap: var(--space-1);
    padding: 0 var(--space-2);
    overflow: visible;
  }
  .site-nav__link {
    font-size: var(--text-base);
    padding: var(--space-2) var(--space-3);
  }
  .site-nav__arc {
    display: block;
    align-self: center;
    margin-top: auto;
    width: 128px;
    height: 64px;
    border-radius: 128px 128px 0 0;
    background-color: var(--color-accent);
  }

  .scroll-progress { left: var(--rail-w); }

  .grid { grid-template-columns: repeat(8, minmax(0, 1fr)); }
  .span-1 { grid-column: span 1; }
  .span-2 { grid-column: span 2; }
  .span-3 { grid-column: span 3; }
  .span-4 { grid-column: span 4; }
  .span-5 { grid-column: span 5; }
  .span-6 { grid-column: span 6; }
  .span-7 { grid-column: span 7; }
  .span-8 { grid-column: 1 / -1; }

  .footer-step--index { padding-block: var(--section-y-lg); }
  .quick-rail { right: var(--space-6); bottom: var(--space-6); }
}

@media (min-width: 1280px) {
  .footer-index { grid-template-columns: 1.6fr 1fr 1fr; }
}

@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;
  }
  .js [data-reveal] {
    opacity: 1;
    transform: none;
  }
  .direct-card:hover::after { transform: none; }
}