/* =========================================================
   博奥赛场 / site.css — 共享外壳样式
   1. reset  2. 变量  3. 基础排版  4. 布局容器  5. 按钮
   6. Bento 面板  7. 文本与数据组件  8. 图像容器  9. 横带
   10. 侧边轨道头部  11. 页脚  12. 返回顶部  13. 动效  14. 响应式
   ========================================================= */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

body { margin: 0; }

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

button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; cursor: pointer; }

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

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

h1, h2, h3, h4, h5, p, figure, blockquote { margin: 0; }

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

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 3px;
}

::selection { background: var(--orange); color: #0B1B3A; }

/* 2. 变量 -------------------------------------------------- */
:root {
  --ink: #0B1B3A;
  --ink-deep: #081326;
  --panel-base: #161C2B;
  --teal: #0E3238;
  --violet: #241A44;
  --wine: #5A1730;
  --orange: #FF6B1A;
  --cyan: #25D8C7;
  --amber: #F5B946;
  --silver: #D9E2F0;
  --white: #FFFFFF;

  --line: rgba(217, 226, 240, .16);
  --line-strong: rgba(217, 226, 240, .30);

  --rail-w: 264px;
  --bar-h: 64px;
  --maxw: 1200px;
  --gutter: clamp(18px, 4vw, 64px);

  --r-l: 26px;
  --r-m: 16px;
  --r-s: 10px;

  --font-display: "Barlow Condensed", "Arial Narrow", "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --shadow-lift: 0 16px 40px rgba(3, 7, 16, .42);
}

/* 3. 基础排版 ---------------------------------------------- */
body {
  background-color: var(--ink);
  background-image:
    radial-gradient(1100px 620px at 8% -12%, rgba(255, 107, 26, .17), rgba(255, 107, 26, 0) 62%),
    radial-gradient(900px 700px at 104% 3%, rgba(37, 216, 199, .13), rgba(37, 216, 199, 0) 66%),
    linear-gradient(180deg, #0B1B3A 0%, #0A1730 52%, #081326 100%);
  background-attachment: fixed;
  color: var(--silver);
  font-family: var(--font-body);
  font-size: clamp(15px, 1.05vw, 17px);
  font-weight: 400;
  line-height: 1.8;
  letter-spacing: .012em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* 22° 斜向颗粒纹理，呼应赛场动势 */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 3;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    22deg,
    rgba(217, 226, 240, .035) 0 1px,
    rgba(217, 226, 240, 0) 1px 6px
  );
  opacity: .8;
}

main:focus { outline: none; }
#main-content { scroll-margin-top: 84px; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.06;
  letter-spacing: -.015em;
  color: var(--white);
  text-wrap: balance;
}
h1 { font-size: clamp(32px, 5vw, 64px); }
h2 { font-size: clamp(26px, 3.4vw, 44px); }
h3 { font-size: clamp(20px, 2.2vw, 28px); }
h4 { font-size: clamp(17px, 1.6vw, 20px); }

.display {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(44px, 8vw, 112px);
  line-height: .94;
  letter-spacing: -.03em;
  color: var(--white);
  text-wrap: balance;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--cyan);
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--orange), var(--amber));
  transform: skewX(-22deg);
}

.lede {
  max-width: 58ch;
  font-size: clamp(16px, 1.4vw, 20px);
  line-height: 1.78;
  color: rgba(217, 226, 240, .78);
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}

.prose {
  max-width: 68ch;
  color: rgba(217, 226, 240, .82);
}
.prose p { margin-block: 1em; }
.prose h2, .prose h3 { margin-block: .7em .3em; }
.prose a {
  color: var(--cyan);
  border-bottom: 1px solid rgba(37, 216, 199, .45);
}
.prose a:hover { border-bottom-color: var(--orange); color: var(--orange); }
.prose ul:not([class]) { display: flex; flex-direction: column; gap: .45em; }
.prose ul:not([class]) li { position: relative; padding-left: 20px; }
.prose ul:not([class]) li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .78em;
  width: 9px;
  height: 2px;
  background: var(--orange);
}

.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;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 11px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: rgba(37, 216, 199, .08);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  white-space: nowrap;
}
.tag--amber {
  color: var(--amber);
  border-color: rgba(245, 185, 70, .42);
  background: rgba(245, 185, 70, .1);
}
.tag--orange {
  color: var(--orange);
  border-color: rgba(255, 107, 26, .42);
  background: rgba(255, 107, 26, .1);
}

.rule {
  height: 1px;
  border: 0;
  margin-block: clamp(24px, 3vw, 44px);
  background: var(--line);
}
.rule--accent {
  height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--orange), var(--amber) 34%, var(--cyan) 68%, rgba(37, 216, 199, 0));
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.stat__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 3vw, 38px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--cyan);
}
.stat__label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: rgba(217, 226, 240, .6);
}

/* 4. 布局容器 ---------------------------------------------- */
.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section {
  position: relative;
  padding-block: clamp(52px, 7vw, 108px);
}
.section--teal {
  background-image: linear-gradient(165deg, #0E3238 0%, #0A1F33 72%);
}
.section--violet {
  background-image: linear-gradient(165deg, #241A44 0%, #101B3A 78%);
}
.section--wine {
  background-image: linear-gradient(165deg, #5A1730 0%, #1B1030 82%);
}
.section--silver {
  background-image: linear-gradient(165deg, #E9EFF9 0%, #C7D4E9 100%);
  color: var(--ink);
}
.section--silver h1,
.section--silver h2,
.section--silver h3,
.section--silver .display { color: var(--ink); }
.section--silver .lede,
.section--silver .prose { color: rgba(11, 27, 58, .78); }
.section--silver .eyebrow { color: var(--teal); }
.section--silver .rule { background: rgba(11, 27, 58, .16); }
.section--silver .panel__meta,
.section--silver .stat__label { color: rgba(11, 27, 58, .6); }

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(16px, 2vw, 28px);
}
.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-6 { grid-column: span 6; }
.span-8 { grid-column: span 8; }
.span-12 { grid-column: span 12; }

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  color: rgba(217, 226, 240, .6);
}
.breadcrumbs__item { display: inline-flex; align-items: center; gap: 8px; }
.breadcrumbs__item::after { content: "/"; color: rgba(217, 226, 240, .3); }
.breadcrumbs__item:last-child::after { display: none; }
.breadcrumbs a:hover { color: var(--cyan); }
.breadcrumbs [aria-current="page"] { color: var(--silver); }

/* 5. 按钮 -------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 10px 20px;
  border: 1px solid transparent;
  border-radius: 12px;
  font-weight: 600;
  font-size: 15px;
  line-height: 1.2;
  text-align: center;
  transition: transform .2s ease, background-color .2s ease, border-color .2s ease, color .2s ease, box-shadow .2s ease;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn--primary {
  background: linear-gradient(140deg, #FF8A3D, var(--orange) 52%, #F04E00);
  color: #0B1B3A;
  font-weight: 800;
  border-bottom-left-radius: 3px;
  box-shadow: 0 12px 28px rgba(255, 107, 26, .3);
}
.btn--primary:hover { box-shadow: 0 16px 34px rgba(255, 107, 26, .42); }

.btn--ghost {
  border-color: var(--line-strong);
  color: var(--silver);
  background: rgba(217, 226, 240, .04);
}
.btn--ghost:hover { border-color: var(--cyan); color: var(--cyan); }

.btn--quiet {
  padding-inline: 8px;
  color: rgba(217, 226, 240, .74);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .1em;
}
.btn--quiet:hover { color: var(--orange); }

.btn--block { width: 100%; }

/* 6. Bento 面板 -------------------------------------------- */
.bento {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(14px, 1.6vw, 22px);
}

.panel {
  --accent: var(--orange);
  position: relative;
  padding: clamp(20px, 2.4vw, 34px);
  border: 1px solid var(--line);
  border-radius: var(--r-l) var(--r-m) var(--r-l) var(--r-m);
  background-image: linear-gradient(160deg, rgba(217, 226, 240, .07), rgba(217, 226, 240, .015));
  overflow: hidden;
}
.panel::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), rgba(255, 255, 255, 0));
}
.panel--teal {
  --accent: var(--cyan);
  background-image: linear-gradient(160deg, rgba(14, 50, 56, .92), rgba(11, 27, 58, .66));
}
.panel--violet {
  --accent: #9A86FF;
  background-image: linear-gradient(160deg, rgba(36, 26, 68, .92), rgba(11, 27, 58, .6));
}
.panel--wine {
  --accent: #FF6E9B;
  background-image: linear-gradient(160deg, rgba(90, 23, 48, .9), rgba(11, 27, 58, .6));
}
.panel--silver {
  --accent: var(--ink);
  border-color: rgba(11, 27, 58, .14);
  background-image: linear-gradient(160deg, #E9EFF9, #C9D5E8);
  color: var(--ink);
}
.panel--silver .panel__title { color: var(--ink); }
.panel--silver .panel__meta { color: rgba(11, 27, 58, .62); }

.panel__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(18px, 1.9vw, 25px);
  line-height: 1.14;
  color: var(--white);
}
.panel__meta {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  color: rgba(217, 226, 240, .6);
}

/* 7. 图像容器 ---------------------------------------------- */
.media {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  border-radius: var(--r-m);
  overflow: hidden;
  isolation: isolate;
  background-image: linear-gradient(140deg, #12294F, #0B1B3A 54%, #0E3238);
}
.media--wide { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }

.media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: contrast(1.06) saturate(1.08);
}
.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  mix-blend-mode: overlay;
  opacity: .7;
  background-image: repeating-linear-gradient(
    22deg,
    rgba(255, 255, 255, .08) 0 1px,
    rgba(255, 255, 255, 0) 1px 5px
  );
}
.media__cap {
  position: absolute;
  left: 14px;
  bottom: 12px;
  z-index: 2;
  padding: 4px 11px;
  border-radius: 999px;
  background: rgba(7, 16, 31, .74);
  color: var(--silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
}

/* 8. 横向主题带 -------------------------------------------- */
.strip {
  overflow: hidden;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(14, 50, 56, .7), rgba(11, 27, 58, .7));
}
.strip__track {
  display: flex;
  align-items: center;
  gap: clamp(24px, 3vw, 46px);
  width: max-content;
  padding-block: 14px;
  padding-inline: var(--gutter);
  animation: strip-slide 46s linear infinite;
}
.strip:hover .strip__track,
.strip:focus-within .strip__track { animation-play-state: paused; }

.strip__item {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: rgba(217, 226, 240, .78);
}
.strip__item::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 2px;
  background: var(--orange);
  transform: rotate(22deg) skewX(-8deg);
}
.strip__item:nth-child(even)::before { background: var(--cyan); }

@keyframes strip-slide {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

/* 9. 侧边轨道头部 ------------------------------------------ */
.rail {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 90;
  display: flex;
  flex-direction: column;
  width: var(--rail-w);
  padding: 26px 22px 22px;
  border-right: 1px solid var(--line);
  background-color: #0A1830;
  background-image:
    linear-gradient(198deg, rgba(255, 107, 26, .18), rgba(255, 107, 26, 0) 46%),
    linear-gradient(22deg, rgba(37, 216, 199, .12) 0 6%, rgba(37, 216, 199, 0) 6% 100%),
    linear-gradient(180deg, #0C1F44 0%, #0B1B3A 48%, #07101F 100%);
}

.skip {
  position: absolute;
  left: 16px;
  top: -72px;
  z-index: 120;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 0 0 12px 12px;
  background: var(--cyan);
  color: #04141A;
  font-weight: 700;
  font-size: 14px;
  transition: top .2s ease;
}
.skip:focus { top: 0; }

.rail__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
}
.brand__mark {
  position: relative;
  flex: 0 0 34px;
  width: 34px;
  height: 34px;
  border-radius: 11px 5px 11px 5px;
  overflow: hidden;
  background-image: linear-gradient(150deg, #FF8A3D, var(--orange) 55%, #E23E00);
  box-shadow: 0 10px 22px rgba(255, 107, 26, .32);
}
.brand__mark i {
  position: absolute;
  left: 7px;
  right: 7px;
  height: 3px;
  border-radius: 2px;
  background: var(--ink);
  transform: rotate(-22deg);
}
.brand__mark i:nth-child(1) { top: 9px; }
.brand__mark i:nth-child(2) { top: 16px; }
.brand__mark i:nth-child(3) { top: 23px; }

.brand__text { display: flex; flex-direction: column; }
.brand__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 21px;
  line-height: 1.1;
  letter-spacing: .02em;
  color: var(--white);
}
.brand__line {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .22em;
  color: var(--cyan);
}

.rail__toggle {
  display: none;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  min-width: 44px;
  padding: 8px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 12px;
  color: var(--silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
}
.rail__bars {
  position: relative;
  width: 20px;
  height: 12px;
  flex: 0 0 20px;
}
.rail__bars::before,
.rail__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--orange);
  transition: transform .28s ease, background-color .28s ease;
}
.rail__bars::before { top: 0; }
.rail__bars::after { bottom: 0; }
.rail[data-open] .rail__bars::before { transform: translateY(5px) rotate(45deg); }
.rail[data-open] .rail__bars::after { transform: translateY(-5px) rotate(-45deg); }
.rail[data-open] .rail__toggle-label { color: var(--cyan); }

.rail__nav {
  display: flex;
  flex-direction: column;
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(217, 226, 240, .3) transparent;
}

.rail__navtitle {
  margin: 26px 0 10px;
  padding-left: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .26em;
  color: rgba(217, 226, 240, .42);
}

.rail__list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.rail__link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
  padding: 10px 12px;
  border-radius: 12px;
  color: rgba(217, 226, 240, .82);
  transition: background-color .2s ease, color .2s ease, transform .2s ease;
}
.rail__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  bottom: 12px;
  width: 3px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--orange), var(--amber));
  transform: scaleY(0);
  transform-origin: top center;
  transition: transform .26s ease;
}
.rail__link:hover {
  background: rgba(217, 226, 240, .07);
  color: var(--white);
  transform: translateX(3px);
}
.rail__link[aria-current="page"] {
  background: linear-gradient(90deg, rgba(255, 107, 26, .22), rgba(255, 107, 26, 0));
  color: var(--white);
}
.rail__link[aria-current="page"]::before { transform: scaleY(1); }
.rail__link[aria-current="page"] .rail__idx { color: var(--amber); }

.rail__idx {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--cyan);
}
.rail__label { font-weight: 500; font-size: 15px; }

.rail__quick {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin-top: 22px;
}
.rail__quick .btn { padding: 9px 12px; font-size: 13px; }
.rail__quick .btn:first-child { grid-column: 1 / -1; }

.rail__util {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  margin-top: auto;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
}
.rail__util a {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  color: rgba(217, 226, 240, .58);
}
.rail__util a:hover { color: var(--cyan); }

.rail__meter {
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  width: 3px;
  background: rgba(217, 226, 240, .08);
}
.rail__meter-fill {
  display: block;
  width: 100%;
  height: calc(var(--p, 0) * 1%);
  background: linear-gradient(180deg, var(--cyan), var(--orange));
  transition: height .12s linear;
}

.rail__scrim { display: none; }

/* 10. 页脚 -------------------------------------------------- */
.field {
  position: relative;
  margin-top: clamp(40px, 6vw, 90px);
  padding-block: clamp(44px, 5vw, 76px) 32px;
  border-top: 1px solid var(--line);
  background-color: #07101F;
  background-image:
    linear-gradient(160deg, rgba(90, 23, 48, .6), rgba(90, 23, 48, 0) 58%),
    linear-gradient(200deg, rgba(14, 50, 56, .92), rgba(11, 27, 58, .9) 56%, #07101F 100%);
}
.field::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: linear-gradient(90deg, var(--orange), var(--amber) 28%, var(--cyan) 62%, rgba(37, 216, 199, 0));
}

.field__grid {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 2fr);
  gap: clamp(28px, 4vw, 64px);
  padding-bottom: clamp(26px, 3vw, 46px);
  border-bottom: 1px solid var(--line);
}

.field__summary {
  max-width: 34ch;
  margin-top: 20px;
  font-size: clamp(16px, 1.5vw, 19px);
  line-height: 1.72;
  color: var(--silver);
}
.field__note {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: rgba(217, 226, 240, .46);
}

.field__cols {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(18px, 2vw, 32px);
}
.field__coltitle {
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .22em;
  color: var(--amber);
}
.field__links { display: flex; flex-direction: column; gap: 6px; }
.field__links a {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  color: rgba(217, 226, 240, .78);
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}
.field__links a:hover {
  color: var(--white);
  border-bottom-color: var(--orange);
}

.field__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 30px;
  padding-top: clamp(18px, 2.4vw, 28px);
  font-size: 14px;
  color: rgba(217, 226, 240, .72);
}
.field__key {
  margin-right: 8px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--cyan);
}
.field__icp {
  font-size: 13px;
  color: rgba(217, 226, 240, .56);
}
.field__copy {
  margin-top: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: rgba(217, 226, 240, .48);
}

/* 11. 返回顶部 --------------------------------------------- */
.totop {
  position: fixed;
  right: clamp(14px, 3vw, 28px);
  bottom: clamp(14px, 3vw, 28px);
  z-index: 80;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-width: 48px;
  min-height: 48px;
  padding: 0 16px;
  border-radius: 14px 4px 14px 4px;
  background-image: linear-gradient(140deg, #FF8A3D, var(--orange));
  color: #0B1B3A;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .14em;
  box-shadow: 0 14px 32px rgba(255, 107, 26, .36);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity .25s ease, transform .25s ease, visibility .25s ease;
}
.totop[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: none;
}
.totop:hover { box-shadow: 0 18px 38px rgba(255, 107, 26, .5); }
.totop__arrow { font-size: 15px; line-height: 1; }
.totop__label { display: none; }

/* 12. 动效协议 --------------------------------------------- */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .5s ease, transform .6s cubic-bezier(.22, .8, .28, 1);
}
.js [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* 13. 响应式 ----------------------------------------------- */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }
}

@media (min-width: 560px) {
  .totop__label { display: inline; }
}

@media (max-width: 1023px) {
  body { padding-left: 0; }

  .rail {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    bottom: auto;
    z-index: 95;
    width: 100%;
    height: auto;
    flex-direction: row;
    align-items: center;
    padding: 10px 16px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    background-image: linear-gradient(180deg, #0C1F44, #0A1830);
  }

  .rail__top {
    flex: 1 1 auto;
    min-width: 0;
  }

  .brand__name { font-size: 19px; }

  .rail__toggle { display: inline-flex; }

  .rail__nav {
    position: fixed;
    top: var(--bar-h);
    right: 0;
    bottom: 0;
    left: auto;
    z-index: 92;
    flex: none;
    width: min(86vw, 352px);
    padding: 18px 20px 34px;
    border-left: 1px solid var(--line-strong);
    background-image: linear-gradient(200deg, #12454D 0%, #0E3238 26%, #0B1B3A 66%, #241A44 100%);
    box-shadow: -24px 0 60px rgba(3, 7, 16, .55);
    transform: translateX(104%);
    transition: transform .34s cubic-bezier(.22, .8, .28, 1);
    overflow-y: auto;
  }
  .rail[data-open] .rail__nav { transform: none; }

  .rail__navtitle { margin-top: 6px; }
  .rail__link { min-height: 48px; }
  .rail__label { font-size: 16px; }
  .rail__quick { grid-template-columns: 1fr; }
  .rail__quick .btn:first-child { grid-column: auto; }
  .rail__util { margin-top: 24px; }

  .rail__scrim {
    display: block;
    position: fixed;
    left: 0;
    right: 0;
    top: var(--bar-h);
    bottom: 0;
    z-index: 91;
    background: rgba(4, 9, 20, .7);
  }
  .rail__scrim[hidden] { display: none; }

  .rail__meter {
    top: auto;
    left: 0;
    right: 0;
    bottom: 0;
    width: auto;
    height: 3px;
  }
  .rail__meter-fill {
    height: 100%;
    width: calc(var(--p, 0) * 1%);
    background: linear-gradient(90deg, var(--cyan), var(--orange));
    transition: width .12s linear;
  }

  .field__grid { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 1023px) {
  .span-3,
  .span-4 { grid-column: span 6; }
  .span-8 { grid-column: span 12; }

  .field__links a { min-height: 44px; }
  .field__cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 900px) {
  .field__cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 600px) {
  .span-3,
  .span-4,
  .span-6 { grid-column: span 12; }

  .field__cols { grid-template-columns: minmax(0, 1fr); }
  .field__meta { flex-direction: column; align-items: flex-start; gap: 8px; }
  .panel { border-radius: 20px 12px 20px 12px; }
}

/* 14. 减少动态偏好 ----------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  .strip__track { animation: none; transform: none; }
  .js [data-reveal] { opacity: 1; transform: none; }
  .rail__nav { transition: none; }
  .btn:hover,
  .rail__link:hover { transform: none; }
}