/* ==========================================================================
   博鱼看台 / ocean-boyu.com.cn
   共享样式 /assets/site.css
   设计基因：框架式竖向导轨 + 斜切深水层 + 控球率四色阶分区
   ========================================================================== */

/* --- 0 · 设计令牌 ------------------------------------------------------- */
:root {
  --abyss: #041C2C;
  --deep: #0B3350;
  --paper: #F2EAD9;
  --paper-ink: #10202B;
  --cyan: #37E4D3;
  --lake: #1E8FB5;
  --mist: #A4DCD6;
  --pale: #D8E1E3;
  --amber: #F3A73B;
  --mint: #5FE0A6;
  --signal: #E2543A;
  --slate: #6E8090;

  --rail-w: 96px;
  --bar-h: 62px;
  --shell-max: 1280px;
  --gutter: 28px;

  --font-display: "Barlow Condensed", "Archivo Narrow", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-body: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-serif: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", "SFMono-Regular", "Menlo", "Consolas", monospace;

  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  --shadow-hard: 6px 6px 0 rgba(4, 28, 44, 0.55);
  --hair: rgba(242, 234, 217, 0.16);
  --hair-cyan: rgba(55, 228, 211, 0.4);
}

/* --- 1 · Reset ---------------------------------------------------------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
}

body, h1, h2, h3, h4, h5, p, figure, blockquote, dl, dd, ul, ol, pre { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg, video { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
table { border-collapse: collapse; width: 100%; }
hr { border: 0; }

/* --- 2 · 基底与水下光影 ------------------------------------------------- */
body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--abyss);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: 0.012em;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(90deg, rgba(55, 228, 211, 0.055) 0 1px, transparent 1px 120px),
    repeating-linear-gradient(0deg, rgba(55, 228, 211, 0.035) 0 1px, transparent 1px 120px),
    radial-gradient(1100px 620px at 84% -12%, rgba(30, 143, 181, 0.34), transparent 68%),
    radial-gradient(900px 520px at 6% 112%, rgba(55, 228, 211, 0.1), transparent 70%);
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.04;
  letter-spacing: 0.01em;
}

h1 { font-size: clamp(38px, 7vw, 96px); }
h2 { font-size: clamp(28px, 4.4vw, 56px); }
h3 { font-size: clamp(20px, 2.6vw, 30px); }
h4 { font-size: clamp(17px, 2vw, 22px); font-weight: 500; }

p { text-wrap: pretty; }

@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }
}
@media (max-width: 1023px) {
  body { padding-bottom: calc(var(--bar-h) + 10px); }
}

/* --- 3 · 焦点与可访问工具类 -------------------------------------------- */
:where(a, button, [tabindex], input, select, summary):focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 3px;
  border-radius: 1px;
}

.u-sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.u-hidden { display: none !important; }
.u-mono { font-family: var(--font-mono); }
.u-serif { font-family: var(--font-serif); }
.u-cite { color: var(--slate); font-size: 13px; line-height: 1.6; }

/* --- 4 · 跳转链接 ------------------------------------------------------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 1200;
  padding: 11px 18px;
  background: var(--amber);
  color: #1A1204;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.06em;
  border: 2px solid #1A1204;
  transform: translateY(-180%);
  transition: transform 0.2s var(--ease);
}
.skip-link:focus { transform: translateY(0); }

/* --- 5 · 顶部阅读进度线 ------------------------------------------------- */
.progress-line {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 2px;
  z-index: 1100;
  background: rgba(55, 228, 211, 0.14);
  pointer-events: none;
}
.progress-line__bar {
  display: block;
  width: 0;
  height: 100%;
  background: var(--cyan);
  box-shadow: 0 0 12px rgba(55, 228, 211, 0.75);
  transition: width 0.12s linear;
}

/* --- 6 · 框架式竖向导轨（Header） -------------------------------------- */
.site-rail {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  width: var(--rail-w);
  z-index: 900;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 22px 8px 18px;
  background: linear-gradient(180deg, #041C2C 0%, #0B3350 56%, #041C2C 100%);
  border-right: 3px solid var(--deep);
  box-shadow: 6px 0 0 rgba(4, 28, 44, 0.5);
}

.site-rail::after {
  content: "";
  position: absolute;
  top: 12%; bottom: 12%; right: -3px;
  width: 3px;
  background: linear-gradient(180deg, transparent, var(--cyan) 30%, var(--lake) 72%, transparent);
  opacity: 0.7;
  pointer-events: none;
}

.rail__brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 0 0 16px;
}
.rail__brand-cn {
  writing-mode: vertical-rl;
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--paper);
  padding-bottom: 4px;
}
.rail__brand-en {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.24em;
  color: var(--slate);
}
.rail__brand::after {
  content: "";
  width: 22px;
  height: 3px;
  background: var(--cyan);
}

.rail__toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 9px 12px;
  border: 2px solid rgba(55, 228, 211, 0.5);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  transition: border-color 0.16s var(--ease), color 0.16s var(--ease);
}
.rail__toggle:hover { border-color: var(--cyan); color: var(--cyan); }
.rail__toggle-bars {
  display: flex;
  flex-direction: column;
  gap: 3px;
  width: 16px;
}
.rail__toggle-bars i {
  display: block;
  height: 2px;
  background: currentColor;
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}
.rail__toggle-text { line-height: 1; }

.rail__nav {
  flex: 1 1 auto;
  min-height: 0;
  width: 100%;
  display: flex;
  justify-content: center;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 6px 0;
  scrollbar-width: thin;
  scrollbar-color: rgba(55, 228, 211, 0.4) transparent;
}
.rail__nav::-webkit-scrollbar { width: 4px; }
.rail__nav::-webkit-scrollbar-thumb { background: rgba(55, 228, 211, 0.4); }

.nav-list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  width: 100%;
}
.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 12px 6px;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: rgba(242, 234, 217, 0.72);
  writing-mode: vertical-rl;
  transition: color 0.16s var(--ease), background-color 0.16s var(--ease);
}
.nav-link:hover {
  color: var(--paper);
  background-color: rgba(55, 228, 211, 0.08);
}
.nav-link[aria-current="page"] {
  color: var(--cyan);
  background-color: rgba(55, 228, 211, 0.1);
}
.nav-link[aria-current="page"]::before {
  content: "";
  position: absolute;
  left: 2px; top: 8px; bottom: 8px;
  width: 3px;
  background: var(--cyan);
}

.rail__foot {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding-top: 14px;
  border-top: 1px solid var(--hair);
}
.rail__icp {
  writing-mode: vertical-rl;
  max-height: 140px;
  overflow: hidden;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 9px;
  line-height: 1.35;
  letter-spacing: 0.08em;
  color: var(--slate);
}

.rail__cta {
  position: fixed;
  top: 20px; right: 22px;
  z-index: 960;
  display: inline-flex;
  align-items: center;
  padding: 13px 20px;
  background: var(--amber);
  color: #1A1204;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.08em;
  border: 2px solid #1A1204;
  box-shadow: 5px 5px 0 rgba(4, 28, 44, 0.6);
  transition: transform 0.16s var(--ease), box-shadow 0.16s var(--ease);
}
.rail__cta:hover {
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0 rgba(4, 28, 44, 0.6);
}

/* --- 7 · 页脚 ----------------------------------------------------------- */
.site-foot {
  position: relative;
  z-index: 1;
  margin-top: 110px;
  background-color: var(--deep);
  color: var(--paper);
  overflow: hidden;
}
.foot__cut {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 64px;
  background: var(--abyss);
  clip-path: polygon(0 0, 100% 0, 100% 22%, 0 100%);
  pointer-events: none;
}
.foot__inner {
  position: relative;
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding: 112px var(--gutter) 46px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 42px;
}
.foot__mark {
  font-family: var(--font-display);
  font-size: clamp(44px, 7vw, 86px);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: 0.02em;
  color: var(--paper);
}
.foot__tagline {
  margin-top: 14px;
  font-family: var(--font-serif);
  font-size: 15px;
  letter-spacing: 0.16em;
  color: var(--mist);
}
.foot__nav {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 28px;
}
.foot__col-title {
  padding-bottom: 10px;
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
  border-bottom: 1px solid rgba(55, 228, 211, 0.28);
}
.foot__list { display: grid; gap: 10px; }
.foot__list a {
  font-size: 15px;
  color: rgba(242, 234, 217, 0.78);
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}
.foot__list a:hover {
  color: var(--cyan);
  border-bottom-color: rgba(55, 228, 211, 0.55);
}

.contact-list { display: grid; gap: 16px; }
.contact-list__label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--slate);
}
.contact-list__value {
  display: block;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.65;
  color: var(--paper);
  word-break: break-word;
}
.copy-btn {
  display: inline-flex;
  align-items: center;
  margin-top: 7px;
  padding: 5px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--cyan);
  border: 1px solid var(--hair-cyan);
  transition: background-color 0.16s var(--ease), color 0.16s var(--ease), border-color 0.16s var(--ease);
}
.copy-btn:hover { background-color: var(--cyan); color: var(--abyss); border-color: var(--cyan); }
.copy-btn.is-done {
  background-color: var(--mint);
  border-color: var(--mint);
  color: var(--abyss);
}
.foot__note {
  margin-top: 20px;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--slate);
}
.foot__base {
  position: relative;
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding: 20px var(--gutter) 40px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  border-top: 1px solid var(--hair);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--slate);
}
.foot__icp { color: var(--mist); }

/* --- 8 · 按钮 ----------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 24px;
  background: var(--cyan);
  color: var(--abyss);
  border: 2px solid var(--cyan);
  box-shadow: var(--shadow-hard);
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.06em;
  transition: transform 0.16s var(--ease), box-shadow 0.16s var(--ease), background-color 0.16s var(--ease);
}
.btn:hover { transform: translate(-2px, -2px); box-shadow: 9px 9px 0 rgba(4, 28, 44, 0.55); }
.btn:active { transform: translate(2px, 2px); box-shadow: 2px 2px 0 rgba(4, 28, 44, 0.55); }
.btn--amber { background: var(--amber); border-color: var(--amber); color: #1A1204; }
.btn--ghost {
  background: transparent;
  color: var(--paper);
  border-color: rgba(242, 234, 217, 0.45);
  box-shadow: none;
}
.btn--ghost:hover {
  border-color: var(--cyan);
  color: var(--cyan);
  box-shadow: none;
  transform: translateY(-2px);
}
.btn--block { display: flex; width: 100%; justify-content: center; }

/* --- 9 · 面包屑 --------------------------------------------------------- */
.crumbs {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--slate);
}
.crumbs ol { display: flex; flex-wrap: wrap; gap: 8px; }
.crumbs li { display: flex; align-items: center; gap: 8px; }
.crumbs li + li::before { content: "/"; color: var(--lake); }
.crumbs a { color: var(--mist); transition: color 0.16s var(--ease); }
.crumbs a:hover { color: var(--cyan); }
.crumbs [aria-current="page"] { color: var(--paper); }

/* --- 10 · 容器与正文 ---------------------------------------------------- */
.shell {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.shell--tight { max-width: 940px; }

.prose {
  max-width: 74ch;
  font-size: 17px;
  line-height: 1.85;
  color: rgba(242, 234, 217, 0.9);
}
.prose > * + * { margin-top: 1.05em; }
.prose h2 { margin-top: 2.2em; color: var(--paper); }
.prose h3 { margin-top: 1.8em; color: var(--mist); font-weight: 500; }
.prose a { color: var(--cyan); border-bottom: 1px solid rgba(55, 228, 211, 0.4); }
.prose a:hover { border-bottom-color: var(--cyan); }
.prose ul, .prose ol { display: grid; gap: 0.55em; }
.prose ul li { position: relative; padding-left: 24px; }
.prose ul li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.78em;
  width: 11px; height: 3px;
  background: var(--cyan);
}
.prose ol { counter-reset: prose-ol; }
.prose ol li { position: relative; padding-left: 30px; counter-increment: prose-ol; }
.prose ol li::before {
  content: counter(prose-ol, decimal-leading-zero);
  position: absolute;
  left: 0; top: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--amber);
}
.prose strong { color: var(--paper); font-weight: 700; }
.prose blockquote {
  padding: 20px 24px;
  background: rgba(11, 51, 80, 0.6);
  border-left: 3px solid var(--cyan);
  font-family: var(--font-serif);
  color: var(--mist);
}
.prose--paper {
  padding: 36px clamp(20px, 3vw, 46px);
  background: var(--paper);
  color: var(--paper-ink);
  border: 3px solid var(--deep);
  box-shadow: var(--shadow-hard);
}
.prose--paper h2, .prose--paper h3, .prose--paper strong { color: var(--paper-ink); }
.prose--paper a { color: #0B5A6E; border-bottom-color: rgba(11, 90, 110, 0.45); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
}
.eyebrow::before { content: ""; width: 26px; height: 2px; background: var(--cyan); }

.section-title { margin-top: 14px; color: var(--paper); }

.divider {
  height: 3px;
  border: 0;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--lake) 38%, rgba(242, 234, 217, 0.14) 100%);
}

/* --- 11 · 网格 ---------------------------------------------------------- */
.grid { display: grid; gap: 24px; }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.grid--split { grid-template-columns: 1fr; }
@media (min-width: 1024px) {
  .grid--split { grid-template-columns: 1fr 1.9fr; gap: 40px; }
}

/* --- 12 · 数据展示 ------------------------------------------------------ */
.data-table {
  width: 100%;
  font-size: 14px;
  line-height: 1.7;
  font-variant-numeric: tabular-nums;
  color: var(--paper);
}
.data-table caption {
  padding-bottom: 12px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--slate);
}
.data-table th, .data-table td {
  padding: 11px 14px;
  text-align: left;
  white-space: nowrap;
  border-bottom: 1px solid var(--hair);
}
.data-table thead th {
  position: sticky;
  top: 0;
  z-index: 2;
  background: var(--paper);
  color: var(--paper-ink);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  border-bottom: 3px solid var(--abyss);
}
.data-table tbody tr { background: rgba(4, 28, 44, 0.35); }
.data-table tbody tr:nth-child(even) { background: rgba(216, 225, 227, 0.07); }
.data-table tbody tr:hover { background: rgba(55, 228, 211, 0.09); }
.data-table tbody th { font-weight: 500; color: var(--mist); }

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
  white-space: nowrap;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  border: 1px solid currentColor;
  white-space: nowrap;
}
.tag--cyan { color: var(--cyan); }
.tag--amber { color: var(--amber); }
.tag--mint { color: var(--mint); }
.tag--signal { color: var(--signal); }

.scale-bar {
  display: flex;
  height: 10px;
  border: 1px solid rgba(242, 234, 217, 0.28);
}
.scale-bar__seg { flex: 1; }
.scale-bar__seg--1 { background: var(--deep); }
.scale-bar__seg--2 { background: var(--lake); }
.scale-bar__seg--3 { background: var(--mist); }
.scale-bar__seg--4 { background: var(--pale); }

/* --- 13 · 图片容器（页面阶段放置素材） --------------------------------- */
.media-frame {
  position: relative;
  overflow: hidden;
  background: linear-gradient(160deg, #0B3350, #041C2C);
  border: 3px solid var(--deep);
  box-shadow: var(--shadow-hard);
}
.media-frame img,
.media-frame > svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(55, 228, 211, 0.16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(55, 228, 211, 0.16) 1px, transparent 1px);
  background-size: 48px 48px;
  mix-blend-mode: screen;
}
.media-frame--16x9 { aspect-ratio: 16 / 9; }
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame figcaption {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  z-index: 2;
  padding: 10px 14px;
  background: rgba(4, 28, 44, 0.82);
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--mist);
}

/* --- 14 · 显现动效 ------------------------------------------------------ */
@media (scripting: enabled) {
  [data-reveal] {
    opacity: 0;
    transform: translateY(12px);
    transition: opacity 0.32s var(--ease), transform 0.32s var(--ease);
  }
  [data-reveal].is-visible {
    opacity: 1;
    transform: none;
  }
}

/* --- 15 · 断点：平板与窄屏 ---------------------------------------------- */
@media (min-width: 768px) {
  .foot__inner { grid-template-columns: 1fr 1fr; }
  .foot__mark { grid-column: 1 / -1; }
}
@media (min-width: 768px) and (max-width: 1023px) {
  .foot__contact { grid-column: 1 / -1; }
}
@media (min-width: 1024px) {
  .foot__inner { grid-template-columns: 1.25fr 2.1fr 1.5fr; gap: 48px; }
  .foot__mark { grid-column: auto; }
}

@media (max-width: 1023px) {
  .site-rail {
    top: auto; bottom: 0; left: 0; right: 0;
    width: auto;
    height: var(--bar-h);
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 0 12px;
    border-right: 0;
    border-top: 3px solid var(--deep);
    box-shadow: 0 -6px 0 rgba(4, 28, 44, 0.42);
  }
  .site-rail::after { display: none; }

  .rail__brand {
    flex-direction: row;
    align-items: center;
    gap: 10px;
    width: auto;
    padding: 0;
  }
  .rail__brand-cn {
    writing-mode: horizontal-tb;
    font-size: 19px;
    letter-spacing: 0.08em;
    padding: 0;
  }
  .rail__brand-en,
  .rail__brand::after { display: none; }

  .rail__toggle { display: inline-flex; }
  .site-rail[data-open] .rail__toggle-bars i:nth-child(1) { transform: translateY(5px) rotate(45deg); }
  .site-rail[data-open] .rail__toggle-bars i:nth-child(2) { opacity: 0; }
  .site-rail[data-open] .rail__toggle-bars i:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

  .rail__nav {
    position: absolute;
    left: 0; right: 0; bottom: 100%;
    width: auto;
    max-height: 0;
    visibility: hidden;
    justify-content: stretch;
    background: var(--deep);
    border-top: 2px solid var(--hair-cyan);
    transition: max-height 0.3s var(--ease), visibility 0.3s var(--ease);
  }
  .site-rail[data-open] .rail__nav {
    max-height: 74vh;
    visibility: visible;
  }
  .nav-list { flex-direction: column; align-items: stretch; gap: 0; }
  .nav-link {
    writing-mode: horizontal-tb;
    justify-content: flex-start;
    padding: 15px 20px;
    font-size: 16px;
    letter-spacing: 0.06em;
    border-bottom: 1px solid var(--hair);
  }
  .nav-link[aria-current="page"]::before {
    left: 0; top: 0; bottom: 0;
    width: 4px;
  }

  .rail__foot {
    flex-direction: row;
    align-items: center;
    width: auto;
    padding: 0;
    border-top: 0;
  }
  .rail__icp { display: none; }

  .rail__cta {
    position: static;
    padding: 10px 14px;
    font-size: 14px;
    box-shadow: 3px 3px 0 rgba(4, 28, 44, 0.6);
  }
  .rail__cta:hover { transform: none; box-shadow: 3px 3px 0 rgba(4, 28, 44, 0.6); }

  .foot__inner { padding-top: 96px; }
}

@media (max-width: 560px) {
  :root { --gutter: 18px; }
  .rail__cta { font-size: 13px; padding: 9px 11px; }
  .rail__brand-cn { font-size: 17px; }
  .foot__base { flex-direction: column; align-items: flex-start; }
}

/* --- 16 · 动效降级 ------------------------------------------------------ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .progress-line__bar { transition: none; }
  [data-reveal] { opacity: 1 !important; transform: none !important; }
}