/* =========================================================
   冰雪游艺 · 共享样式 /assets/site.css
   1 reset  2 tokens  3 base  4 通用组件  5 头部冰晶轨道
   6 页脚  7 悬浮控件  8 响应式  9 可访问性
   ========================================================= */

/* ---------- 1. reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body,
h1, h2, h3, h4, p, ul, ol, figure, blockquote, dl, dd { margin: 0; }

ul, ol { padding: 0; list-style: none; }

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

img { height: auto; }

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

a { color: inherit; text-decoration: none; }

table { border-collapse: collapse; width: 100%; }

/* ---------- 2. tokens ---------- */
:root {
  --ink-950: #061A2E;
  --ink-900: #0A2440;
  --blue-700: #124E8C;
  --blue-500: #2C8FE0;
  --cyan-400: #3FD6D0;
  --white: #FFFFFF;
  --frost-050: #F1F7FD;
  --line-200: #C9DEF3;
  --orange-500: #FF7A33;
  --mint-300: #8CE0BE;
  --text-700: #27384A;
  --text-500: #5A7188;

  --rail-w: 88px;
  --rail-w-lg: 240px;
  --topbar-h: 64px;
  --content-max: 1240px;

  --r-sm: 12px;
  --r-md: 20px;
  --r-lg: 28px;
  --r-pill: 999px;

  --shadow-soft: 0 18px 40px -26px rgba(18, 78, 140, 0.45);
  --shadow-float: 0 28px 62px -30px rgba(6, 26, 46, 0.55);

  --ease: cubic-bezier(0.4, 0, 0.2, 1);

  --font-sans: "HarmonyOS Sans SC", "Inter Tight", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "Source Han Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

/* ---------- 3. base ---------- */
body {
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.75;
  color: var(--text-700);
  background-color: var(--white);
  min-height: 100vh;
  padding-left: 0;
  padding-top: var(--topbar-h);
  -webkit-font-smoothing: antialiased;
}

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

h1, h2, h3, h4 {
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.24;
  color: var(--ink-950);
}

h1 { font-size: clamp(30px, 4.4vw, 50px); }
h2 { font-size: clamp(24px, 3vw, 36px); }
h3 { font-size: clamp(19px, 2vw, 23px); }

p { max-width: 68ch; }

strong { color: var(--ink-950); }

::selection { background: rgba(63, 214, 208, 0.28); color: var(--ink-950); }

#main-content { display: block; min-height: 60vh; }
#main-content:focus { outline: none; }

/* ---------- 4. 通用组件 ---------- */
.wrap {
  width: min(100% - 40px, var(--content-max));
  margin-inline: auto;
}

.wrap--narrow { width: min(100% - 40px, 880px); }

.section { padding: clamp(56px, 8vw, 96px) 0; }
.section--tight { padding: clamp(34px, 5vw, 56px) 0; }

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px 32px;
  margin-bottom: clamp(24px, 3vw, 36px);
}

.section-head__title { font-size: clamp(24px, 3vw, 36px); }

.section-head__desc {
  max-width: 52ch;
  font-size: 15.5px;
  color: var(--text-500);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--blue-700);
}

.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: linear-gradient(90deg, var(--cyan-400), rgba(63, 214, 208, 0));
}

.lead {
  font-size: 17.5px;
  line-height: 1.8;
  color: var(--text-500);
  max-width: 62ch;
}

.display-1 { font-size: clamp(32px, 5vw, 58px); line-height: 1.12; }

.display-2 { font-size: clamp(26px, 3.4vw, 40px); line-height: 1.18; }

.grad-text {
  background: linear-gradient(100deg, var(--blue-700) 0%, var(--blue-500) 46%, var(--cyan-400) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.mono {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--blue-700);
}

/* 面包屑 */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text-500);
  margin: 30px 0 16px;
}

.crumbs li { display: inline-flex; align-items: center; }
.crumbs li + li::before { content: "/"; margin-right: 8px; color: var(--line-200); }
.crumbs a { color: var(--blue-700); }
.crumbs a:hover { color: var(--cyan-400); }
.crumbs [aria-current="page"] { color: var(--ink-950); }

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 26px;
  border-radius: var(--r-pill);
  border: 1px solid transparent;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.2;
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease), background-color 0.2s var(--ease);
}

.btn:hover { transform: translateY(-2px); }

.btn--primary {
  background: linear-gradient(120deg, var(--blue-500), var(--cyan-400));
  color: #04121F;
  box-shadow: 0 16px 32px -16px rgba(44, 143, 224, 0.8);
}

.btn--ghost {
  background: rgba(255, 255, 255, 0.75);
  border-color: var(--line-200);
  color: var(--blue-700);
}

.btn--orange {
  background: linear-gradient(120deg, var(--orange-500), #FFB073);
  color: #3A1500;
  box-shadow: 0 16px 32px -18px rgba(255, 122, 51, 0.85);
}

/* 卡片 */
.card {
  background: var(--white);
  border: 1px solid var(--line-200);
  border-radius: var(--r-lg);
  padding: clamp(20px, 3vw, 30px);
  box-shadow: var(--shadow-soft);
}

.glass-card {
  background: linear-gradient(150deg, rgba(255, 255, 255, 0.86), rgba(241, 247, 253, 0.62));
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: var(--r-lg);
  padding: clamp(20px, 3vw, 28px);
  box-shadow: var(--shadow-float);
}

.card, .glass-card, .index-track__row { transition: transform 0.24s var(--ease), box-shadow 0.24s var(--ease), border-color 0.24s var(--ease); }
.card:hover, .glass-card:hover { transform: translateY(-4px); border-color: var(--cyan-400); }

/* 冰晶切角 */
.cut-tr {
  clip-path: polygon(0 0, calc(100% - 34px) 0, 100% 34px, 100% 100%, 0 100%);
}

.cut-bl {
  clip-path: polygon(0 0, 100% 0, 100% 100%, 34px 100%, 0 calc(100% - 34px));
}

/* 索引轨 */
.index-track { border-top: 1px solid var(--line-200); }

.index-track__row {
  display: grid;
  grid-template-columns: 68px minmax(150px, 1fr) minmax(0, 1.5fr) auto;
  gap: 20px;
  align-items: center;
  padding: 20px 12px;
  border-bottom: 1px solid var(--line-200);
}

.index-track__row:hover {
  background: linear-gradient(90deg, rgba(63, 214, 208, 0.1), rgba(63, 214, 208, 0));
}

.index-track__num {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--cyan-400);
}

.index-track__name { font-weight: 700; font-size: 17px; color: var(--ink-950); }

.index-track__desc { font-size: 14.5px; color: var(--text-500); }

/* 状态条 */
.status-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 28px;
  padding: 14px 24px;
  border-radius: var(--r-pill);
  border: 1px solid var(--line-200);
  background: linear-gradient(120deg, rgba(241, 247, 253, 0.94), rgba(223, 246, 247, 0.72));
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--blue-700);
}

.status-strip__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--mint-300);
  box-shadow: 0 0 0 4px rgba(140, 224, 190, 0.24);
}

/* 旁注轨道 */
.note-rail {
  border-left: 2px solid var(--line-200);
  padding-left: 18px;
  font-size: 14.5px;
  color: var(--text-500);
}

.note-rail strong { display: block; font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.12em; color: var(--blue-700); margin-bottom: 6px; }

/* 图片容器（页面阶段放入 <img>） */
.media-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--r-lg);
  border: 1px solid var(--line-200);
  background: linear-gradient(150deg, #E7F2FC 0%, #FFFFFF 46%, #DFF6F7 100%);
}

.media-frame > img { width: 100%; height: 100%; object-fit: cover; }

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, 0.75) 1px, transparent 1px);
  background-size: 22px 22px;
  opacity: 0.12;
  pointer-events: none;
}

.media-frame--16x9 { aspect-ratio: 16 / 9; }
.media-frame--3x2 { aspect-ratio: 3 / 2; }
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame--3x4 { aspect-ratio: 3 / 4; }

.media-frame__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 1;
  padding: 16px 20px;
  font-size: 13px;
  color: #EAF4FF;
  background: linear-gradient(180deg, rgba(6, 26, 46, 0), rgba(6, 26, 46, 0.8));
}

/* 网格 */
.grid { display: grid; gap: 24px; }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--auto { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }

/* 显现 */
html.js [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
}

html.js [data-reveal].is-in { opacity: 1; transform: none; }

/* ---------- 5. 头部冰晶轨道 ---------- */
.ice-rail {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 60;
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  height: var(--topbar-h);
  padding: 0 14px;
  color: #EAF4FF;
  background:
    radial-gradient(circle at 18% 12%, rgba(63, 214, 208, 0.14), transparent 46%),
    linear-gradient(180deg, var(--ink-950) 0%, #0E3253 52%, var(--ink-950) 100%);
  border-bottom: 1px solid rgba(201, 222, 243, 0.16);
}

.rail__top {
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  width: 100%;
  padding: 0;
  border: 0;
}

.rail__brand {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 10px;
  padding: 0;
  border-radius: var(--r-sm);
}

.rail__mark { display: block; width: 30px; height: 30px; flex: 0 0 auto; }
.rail__mark svg { width: 100%; height: 100%; }

.rail__brand-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1px;
  line-height: 1.2;
  min-width: 0;
}

.rail__wordmark {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: #FFFFFF;
  white-space: nowrap;
}

.rail__sub {
  display: none;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.2em;
  color: #7FA8CC;
  white-space: nowrap;
  transition: opacity 0.25s var(--ease);
}

/* 移动端开关 */
.rail__toggle {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 8px 14px 8px 12px;
  border-radius: var(--r-pill);
  border: 1px solid rgba(201, 222, 243, 0.3);
  color: #EAF4FF;
  font-size: 13px;
  letter-spacing: 0.08em;
  transition: border-color 0.2s var(--ease), background-color 0.2s var(--ease);
}

.rail__toggle:hover { border-color: var(--cyan-400); background: rgba(63, 214, 208, 0.1); }

.rail__toggle-bars { display: inline-flex; flex-direction: column; gap: 3px; width: 16px; }

.rail__toggle-bars i {
  display: block;
  height: 1.6px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--cyan-400), var(--blue-500));
  transition: transform 0.25s var(--ease), opacity 0.2s var(--ease);
}

.rail__toggle-bars i:nth-child(2) { width: 68%; }

.ice-rail[data-open="true"] .rail__toggle-bars i:nth-child(1) { transform: translateY(4.6px) rotate(45deg); }
.ice-rail[data-open="true"] .rail__toggle-bars i:nth-child(2) { opacity: 0; }
.ice-rail[data-open="true"] .rail__toggle-bars i:nth-child(3) { transform: translateY(-4.6px) rotate(-45deg); }

/* 抽屉 / 轨道容器 */
.rail__drawer {
  position: fixed;
  left: 10px;
  right: 10px;
  bottom: 10px;
  top: auto;
  max-height: min(78vh, 620px);
  padding: 18px 14px 16px;
  border-radius: 26px;
  border: 1px solid rgba(201, 222, 243, 0.22);
  background: linear-gradient(180deg, rgba(10, 36, 64, 0.98), rgba(6, 26, 46, 0.99));
  box-shadow: 0 30px 70px -20px rgba(6, 26, 46, 0.78);
  overflow-y: auto;
  visibility: hidden;
  transform: translate3d(0, calc(100% + 40px), 0);
  transition: transform 0.34s var(--ease), visibility 0.34s var(--ease);
}

.ice-rail[data-open="true"] .rail__drawer { visibility: visible; transform: translate3d(0, 0, 0); }

.rail__nav { display: block; }

.rail__track { position: relative; display: block; }

.rail__ink {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  height: 44px;
  border-radius: 16px;
  border: 1px solid rgba(63, 214, 208, 0.36);
  background: linear-gradient(120deg, rgba(63, 214, 208, 0.22), rgba(44, 143, 224, 0.3));
  opacity: 0;
  pointer-events: none;
  transition: transform 0.2s var(--ease), height 0.2s var(--ease), opacity 0.25s var(--ease);
}

.rail__list {
  position: static;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 6px;
}

.rail__item { margin: 0; }

.rail__link {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 12px;
  padding: 12px;
  border-radius: 16px;
  color: #CFE4F7;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease);
}

.rail__link:hover { color: #FFFFFF; background: rgba(201, 222, 243, 0.08); }

.rail__link.is-active { color: #FFFFFF; }

.rail__num {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--cyan-400);
  flex: 0 0 auto;
}

.rail__text { display: flex; flex-direction: column; align-items: flex-start; gap: 2px; min-width: 0; }

.rail__label { font-size: 13px; line-height: 1.35; color: inherit; }

.rail__note { display: none; }

.rail__link[aria-current="page"] { background: rgba(63, 214, 208, 0.12); }
.rail__link[aria-current="page"] .rail__num { color: var(--mint-300); }

.rail__foot {
  display: flex;
  flex-direction: row;
  gap: 10px;
  padding: 14px 0 0;
  margin-top: 14px;
  border-top: 1px solid rgba(201, 222, 243, 0.16);
}

.rail__cta,
.rail__ghost {
  flex: 1 1 auto;
  padding: 10px 8px;
  border-radius: var(--r-pill);
  font-size: 12.5px;
  font-weight: 700;
  text-align: center;
  white-space: nowrap;
}

.rail__cta {
  background: linear-gradient(120deg, var(--blue-500), var(--cyan-400));
  color: #04121F;
}

.rail__ghost {
  border: 1px solid rgba(201, 222, 243, 0.32);
  color: #CFE4F7;
  font-weight: 400;
}

.rail__scrim {
  position: fixed;
  inset: 0;
  z-index: -1;
  background: rgba(6, 26, 46, 0.58);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.3s var(--ease), visibility 0.3s var(--ease);
}

.ice-rail[data-open="true"] .rail__scrim { opacity: 1; visibility: visible; pointer-events: auto; }

/* 桌面端：左侧冰晶轨道 */
@media (min-width: 1024px) {
  .ice-rail {
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    width: var(--rail-w);
    height: 100vh;
    height: 100dvh;
    padding: 20px 0 16px;
    border-bottom: 0;
    border-right: 1px solid rgba(201, 222, 243, 0.16);
    transition: width 0.28s var(--ease), box-shadow 0.28s var(--ease);
  }

  .ice-rail:hover,
  .ice-rail:focus-within {
    width: var(--rail-w-lg);
    box-shadow: 30px 0 70px -42px rgba(6, 26, 46, 0.9);
  }

  .rail__top {
    flex-direction: column;
    align-items: center;
    gap: 12px;
    padding: 0 10px 16px;
    border-bottom: 1px solid rgba(201, 222, 243, 0.14);
  }

  .rail__brand { flex-direction: column; gap: 8px; }
  .rail__brand-text { align-items: center; }
  .rail__wordmark { font-size: 13px; letter-spacing: 0.08em; }

  .rail__sub { display: block; opacity: 0; }

  .ice-rail:hover .rail__sub,
  .ice-rail:focus-within .rail__sub { opacity: 1; }

  .rail__toggle { display: none; }

  .rail__drawer {
    position: static;
    display: flex;
    flex-direction: column;
    flex: 1 1 auto;
    min-height: 0;
    max-height: none;
    width: auto;
    padding: 12px 10px 0;
    border: 0;
    border-radius: 0;
    background: none;
    box-shadow: none;
    overflow: visible;
    visibility: visible;
    transform: none;
    transition: none;
  }

  .rail__nav { flex: 1 1 auto; min-height: 0; overflow-y: auto; overflow-x: hidden; padding-bottom: 6px; }

  .rail__list { display: flex; flex-direction: column; gap: 4px; }

  .rail__link {
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 10px 8px;
    text-align: center;
  }

  .rail__text { align-items: center; }
  .rail__label { font-size: 12.5px; }

  .rail__note {
    display: block;
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    font-size: 11px;
    line-height: 1.5;
    color: #8FB6D6;
    letter-spacing: 0.02em;
    white-space: nowrap;
    transition: max-height 0.25s var(--ease), opacity 0.25s var(--ease);
  }

  .ice-rail:hover .rail__link,
  .ice-rail:focus-within .rail__link {
    flex-direction: row;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    text-align: left;
  }

  .ice-rail:hover .rail__text,
  .ice-rail:focus-within .rail__text { align-items: flex-start; }

  .ice-rail:hover .rail__note,
  .ice-rail:focus-within .rail__note { max-height: 34px; opacity: 1; }

  .rail__foot { flex-direction: column; gap: 8px; padding-top: 14px; margin-top: auto; }
  .rail__cta, .rail__ghost { padding: 9px 6px; font-size: 12px; }
  .rail__scrim { display: none; }
}

@media (min-width: 1024px) and (max-width: 1180px) {
  :root { --content-max: 1000px; }
}

/* ---------- 6. 页脚 ---------- */
.site-foot {
  position: relative;
  overflow: hidden;
  margin-top: clamp(48px, 8vw, 96px);
  padding: clamp(52px, 7vw, 76px) 0 0;
  color: #CFE4F7;
  background:
    radial-gradient(circle at 82% 6%, rgba(63, 214, 208, 0.16), transparent 44%),
    linear-gradient(180deg, var(--ink-950) 0%, #0A2440 62%, var(--ink-950) 100%);
}

.site-foot::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(201, 222, 243, 0.11) 1px, transparent 1px);
  background-size: 28px 28px;
  opacity: 0.85;
  pointer-events: none;
}

.foot-flake {
  position: absolute;
  top: -12px;
  left: 8%;
  z-index: 0;
  width: 42px;
  height: 42px;
  color: rgba(201, 222, 243, 0.55);
  pointer-events: none;
  animation: flake-drift 26s linear infinite;
}

.foot-flake svg { width: 100%; height: 100%; }

@keyframes flake-drift {
  0% { transform: translate3d(0, 0, 0) rotate(0deg); opacity: 0; }
  14% { opacity: 0.6; }
  86% { opacity: 0.6; }
  100% { transform: translate3d(120px, 340px, 0) rotate(170deg); opacity: 0; }
}

.site-foot__inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.35fr;
  gap: 40px 32px;
  width: min(100% - 40px, var(--content-max));
  margin-inline: auto;
  padding-bottom: clamp(32px, 4vw, 48px);
}

.foot-brand__name {
  font-size: 21px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: #FFFFFF;
  margin-bottom: 12px;
}

.foot-brand__desc { font-size: 14.5px; line-height: 1.8; color: #A8C6E0; max-width: 34ch; }

.foot-brand__code {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: #6E96BA;
}

.foot-col__title {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--cyan-400);
  margin-bottom: 16px;
}

.foot-col__list { display: flex; flex-direction: column; gap: 10px; }

.foot-col__item { font-size: 14.5px; line-height: 1.6; color: #A8C6E0; }

.foot-col__link {
  display: inline-block;
  font-size: 14.5px;
  color: #CFE4F7;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.foot-col__link:hover { color: #FFFFFF; border-color: var(--cyan-400); }

.foot-col__list--contact { gap: 12px; margin-bottom: 20px; }

.foot-contact__label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: #6E96BA;
}

.foot-contact__value { display: block; color: #DCEAF7; word-break: break-word; }

.foot-col__list--legal { gap: 8px; padding-top: 16px; border-top: 1px solid rgba(201, 222, 243, 0.16); }

.site-foot__base {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  width: min(100% - 40px, var(--content-max));
  margin-inline: auto;
  padding: 20px 0 26px;
  border-top: 1px solid rgba(201, 222, 243, 0.16);
}

.foot-base__icp,
.foot-base__copy {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: #6E96BA;
  max-width: none;
}

/* ---------- 7. 悬浮控件 ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  height: 3px;
  pointer-events: none;
}

.scroll-progress span {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cyan-400), var(--blue-500) 62%, var(--orange-500));
  transition: transform 0.1s linear;
}

@media (min-width: 1024px) {
  .scroll-progress { left: var(--rail-w); }
}

.to-top {
  position: fixed;
  right: 18px;
  bottom: 22px;
  z-index: 70;
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  color: #04121F;
  background: linear-gradient(140deg, var(--blue-500), var(--cyan-400));
  box-shadow: 0 16px 34px -14px rgba(18, 78, 140, 0.8);
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0.25s var(--ease);
}

.to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
.to-top:hover { transform: translateY(-3px); }

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 120;
  padding: 11px 20px;
  border-radius: var(--r-pill);
  background: var(--ink-950);
  color: #FFFFFF;
  font-size: 14px;
  box-shadow: var(--shadow-float);
  transform: translateY(-180%);
  transition: transform 0.2s var(--ease);
}

.skip-link:focus { transform: translateY(0); }

.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;
}

/* ---------- 8. 响应式 ---------- */
@media (max-width: 1023px) {
  html.nav-open { overflow: hidden; }
  .rail__list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .index-track__row { grid-template-columns: 56px 1fr; gap: 6px 14px; }
  .index-track__desc { grid-column: 2; }
}

@media (max-width: 900px) {
  .grid--3 { grid-template-columns: 1fr; }
  .site-foot__inner { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 34px 26px; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .grid--2 { grid-template-columns: 1fr; }
  .site-foot__inner { grid-template-columns: 1fr; }
  .rail__list { grid-template-columns: 1fr; }
  .rail__sub { display: none; }
  .status-strip { border-radius: var(--r-md); padding: 12px 18px; }
  .to-top { right: 14px; bottom: 16px; width: 44px; height: 44px; }
}

/* ---------- 9. 可访问性 ---------- */
:focus-visible {
  outline: 2px solid var(--cyan-400);
  outline-offset: 3px;
  border-radius: 6px;
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--cyan-400);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  html.js [data-reveal] { opacity: 1; transform: none; }
  .foot-flake { display: none; }
  .to-top, .rail__ink { transition: none; }
}