/* ============================================================
   特色官网 · /assets/site.css
   共享外壳：侧边轨道导航 + 深色控制台页脚 + 通用内容组件
   ============================================================ */

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

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

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, dl, dd, ol, ul {
  margin: 0;
}

ol, ul { padding: 0; }

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

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

a { color: inherit; }

/* ---------- 2. Tokens ---------- */
:root {
  --ink-900: #071C2C;
  --ink-800: #0C2A40;
  --cyan: #18E0CF;
  --cyan-soft: #8CF8EE;
  --coral: #FF6A45;
  --clay: #C25A3C;
  --cream: #F3EDE2;
  --rock: #6D7A80;
  --moss: #5C7A62;
  --coal: #0E151A;
  --mist: #B9D8D4;
  --sea: #163B4D;

  --rail-w: 240px;
  --topbar-h: 62px;
  --maxw: 1440px;
  --gutter: clamp(18px, 3vw, 44px);

  --font-display: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Courier New", monospace;

  --line: rgba(185, 216, 212, 0.26);
  --line-soft: rgba(185, 216, 212, 0.16);
  --shadow-hard: 8px 8px 0 rgba(3, 12, 18, 0.55);
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --progress: 0;
}

/* ---------- 3. Base / 中文排版 ---------- */
body {
  min-height: 100vh;
  margin: 0;
  padding-left: var(--rail-w);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0.01em;
  color: var(--cream);
  background-color: var(--ink-900);
  background-image:
    linear-gradient(rgba(185, 216, 212, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(185, 216, 212, 0.05) 1px, transparent 1px),
    radial-gradient(120% 70% at 84% -8%, rgba(24, 224, 207, 0.16), transparent 62%),
    radial-gradient(90% 60% at 6% 104%, rgba(255, 106, 69, 0.12), transparent 60%),
    linear-gradient(180deg, #071C2C 0%, #0A2233 48%, #163B4D 100%);
  background-size: 64px 64px, 64px 64px, auto, auto, auto;
  background-attachment: fixed;
  background-repeat: repeat, repeat, no-repeat, no-repeat, no-repeat;
  -webkit-font-smoothing: antialiased;
}

p { max-width: 72ch; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.18;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

:where(a, button, [tabindex]):focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

#main-content { scroll-margin-top: 88px; }

/* ---------- 4. Skip link ---------- */
.skip-link {
  position: fixed;
  top: -120px;
  left: 14px;
  z-index: 300;
  padding: 12px 20px;
  background: var(--cyan);
  color: var(--ink-900);
  border: 2px solid var(--coal);
  font: 600 13px/1 var(--font-mono);
  letter-spacing: 0.08em;
  text-decoration: none;
  transition: top 0.2s var(--ease);
}

.skip-link:focus {
  top: 14px;
}

/* ---------- 5. 侧边轨道 header ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--rail-w);
  z-index: 90;
  background: linear-gradient(180deg, #071C2C 0%, #0C2A40 58%, #163B4D 100%);
  border-right: 2px solid rgba(24, 224, 207, 0.24);
  color: var(--cream);
}

.rail-inner {
  position: relative;
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 22px 16px 20px;
  overflow-y: auto;
  overscroll-behavior: contain;
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--cream);
}

.brand-mark {
  flex: none;
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  background: rgba(24, 224, 207, 0.1);
  border: 2px solid var(--cyan);
  color: var(--cyan);
  font: 700 13px/1 var(--font-mono);
  letter-spacing: 0.06em;
  clip-path: polygon(0 0, 100% 0, 100% 72%, 72% 100%, 0 100%);
  transition: background 0.18s var(--ease), color 0.18s var(--ease);
}

.brand:hover .brand-mark {
  background: var(--cyan);
  color: var(--ink-900);
}

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.brand-name {
  display: block;
  font: 700 16px/1.2 var(--font-display);
  letter-spacing: 0.06em;
}

.brand-sub {
  display: block;
  margin-top: 4px;
  font: 500 10px/1 var(--font-mono);
  letter-spacing: 0.14em;
  color: rgba(185, 216, 212, 0.66);
}

.rail-descriptor {
  margin: 18px 0 14px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line-soft);
  font: 500 10px/1.6 var(--font-mono);
  letter-spacing: 0.18em;
  color: rgba(185, 216, 212, 0.55);
  max-width: none;
}

/* ---------- 6. 导航 ---------- */
.site-nav {
  display: flex;
  flex-direction: column;
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: navi;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.nav-item { margin: 0; }

.nav-link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 10px 10px 12px;
  border-left: 3px solid transparent;
  text-decoration: none;
  color: var(--mist);
  font: 500 14px/1.4 var(--font-display);
  letter-spacing: 0.04em;
  transition: color 0.18s var(--ease), background 0.18s var(--ease), border-color 0.18s var(--ease);
}

.nav-link::before {
  counter-increment: navi;
  content: counter(navi, decimal-leading-zero);
  font: 600 10px/1 var(--font-mono);
  letter-spacing: 0.1em;
  color: rgba(185, 216, 212, 0.5);
  transform: translateY(-1px);
}

.nav-link:hover {
  color: var(--cyan-soft);
  background: rgba(24, 224, 207, 0.08);
  border-left-color: rgba(24, 224, 207, 0.55);
}

.nav-link[aria-current="page"] {
  color: var(--ink-900);
  background: var(--cyan);
  border-left-color: var(--cyan);
  font-weight: 700;
}

.nav-link[aria-current="page"]::before {
  color: rgba(7, 28, 44, 0.72);
}

.nav-tail {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--line-soft);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 14px;
  background: var(--coral);
  color: #1A0A05;
  border: 2px solid var(--coal);
  box-shadow: 4px 4px 0 rgba(3, 12, 18, 0.6);
  font: 700 13px/1 var(--font-display);
  letter-spacing: 0.08em;
  text-decoration: none;
  clip-path: polygon(0 0, 100% 0, 100% 74%, 86% 100%, 0 100%);
  transition: transform 0.16s var(--ease), box-shadow 0.16s var(--ease), background 0.16s var(--ease);
}

.nav-cta:hover {
  transform: translate(-2px, -2px);
  box-shadow: 6px 6px 0 rgba(3, 12, 18, 0.6);
  background: #FF8867;
}

.nav-cta:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 rgba(3, 12, 18, 0.6);
}

.nav-note {
  font: 400 11px/1.65 var(--font-mono);
  letter-spacing: 0.05em;
  color: rgba(185, 216, 212, 0.55);
  max-width: none;
}

/* ---------- 7. 轨道底部 ---------- */
.rail-foot {
  margin-top: auto;
  padding-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.rail-support {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 9px 12px;
  border: 1px dashed rgba(140, 248, 238, 0.42);
  color: var(--cyan-soft);
  text-decoration: none;
  font: 600 11px/1.3 var(--font-mono);
  letter-spacing: 0.1em;
  transition: background 0.18s var(--ease), border-color 0.18s var(--ease);
}

.rail-support:hover {
  background: rgba(24, 224, 207, 0.12);
  border-color: var(--cyan);
}

/* ---------- 8. 滚动进度 ---------- */
.rail-progress {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 3px;
  background: rgba(185, 216, 212, 0.12);
  pointer-events: none;
}

.rail-progress-bar {
  display: block;
  width: 100%;
  height: 100%;
  background: linear-gradient(180deg, var(--cyan), var(--coral));
  transform: scaleY(var(--progress, 0));
  transform-origin: top center;
}

/* ---------- 9. 移动导航按钮与遮罩（桌面隐藏） ---------- */
.nav-toggle { display: none; }

.nav-toggle-icon {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 16px;
}

.nav-toggle-bar {
  display: block;
  width: 100%;
  height: 2px;
  background: currentColor;
  transition: transform 0.22s var(--ease), opacity 0.22s var(--ease);
}

.nav-scrim { display: none; }

/* ---------- 10. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(56px, 8vw, 120px);
  padding: clamp(36px, 5vw, 72px) var(--gutter) 30px;
  color: var(--cream);
  border-top: 2px solid rgba(24, 224, 207, 0.3);
  background-image:
    radial-gradient(90% 70% at 88% 0%, rgba(24, 224, 207, 0.14), transparent 62%),
    radial-gradient(80% 60% at 0% 100%, rgba(255, 106, 69, 0.1), transparent 60%),
    linear-gradient(180deg, #071C2C 0%, #0A2233 58%, #163B4D 100%);
  background-repeat: no-repeat;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  gap: clamp(30px, 4vw, 56px);
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
}

.footer-feedback {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 20px 36px;
  padding: clamp(24px, 3vw, 38px);
  background: var(--coral);
  color: #170703;
  border: 2px solid var(--coal);
  box-shadow: var(--shadow-hard);
}

.footer-feedback-body { min-width: 0; }

.footer-kicker {
  font: 600 10px/1 var(--font-mono);
  letter-spacing: 0.24em;
  color: rgba(23, 7, 3, 0.66);
  max-width: none;
}

.footer-feedback-title {
  margin-top: 10px;
  font: 800 clamp(24px, 3vw, 38px)/1.1 var(--font-display);
  letter-spacing: -0.01em;
  color: #170703;
}

.footer-feedback-text {
  margin-top: 12px;
  max-width: 48ch;
  font: 400 14px/1.75 var(--font-body);
  color: rgba(23, 7, 3, 0.86);
}

.footer-mail {
  margin-top: 14px;
  font: 600 13px/1.5 var(--font-mono);
  letter-spacing: 0.04em;
  color: #170703;
  word-break: break-all;
  max-width: none;
}

.footer-feedback-link {
  justify-self: start;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 22px;
  background: var(--coal);
  color: var(--coral);
  border: 2px solid var(--coal);
  text-decoration: none;
  font: 700 13px/1 var(--font-display);
  letter-spacing: 0.08em;
  transition: transform 0.18s var(--ease), background 0.18s var(--ease), color 0.18s var(--ease);
}

.footer-feedback-link:hover {
  background: var(--cream);
  color: var(--coal);
  transform: translateY(-2px);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 40px);
  padding-top: clamp(22px, 3vw, 34px);
  border-top: 1px solid var(--line-soft);
}

.footer-col {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.footer-col-title {
  margin-bottom: 14px;
  font: 600 10px/1 var(--font-mono);
  letter-spacing: 0.26em;
  color: var(--cyan);
  max-width: none;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-link {
  display: inline-block;
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
  color: var(--mist);
  text-decoration: none;
  font: 400 14px/1.5 var(--font-body);
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.footer-link:hover {
  color: var(--cyan-soft);
  border-bottom-color: currentColor;
}

.footer-meta {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.5fr);
  gap: 22px 48px;
  padding-top: 24px;
  border-top: 1px solid var(--line-soft);
}

.footer-identity { min-width: 0; }

.footer-brand {
  font: 700 15px/1.4 var(--font-display);
  letter-spacing: 0.1em;
  color: var(--cream);
  max-width: none;
}

.footer-legal-line {
  margin-top: 8px;
  font: 400 12px/1.6 var(--font-mono);
  letter-spacing: 0.06em;
  color: rgba(185, 216, 212, 0.62);
  max-width: none;
}

.footer-copy {
  margin-top: 4px;
  font: 400 12px/1.6 var(--font-mono);
  letter-spacing: 0.06em;
  color: rgba(185, 216, 212, 0.5);
  max-width: none;
}

.footer-contact-list {
  list-style: none;
  display: grid;
  gap: 6px;
  font: 400 12px/1.75 var(--font-mono);
  letter-spacing: 0.03em;
  color: rgba(185, 216, 212, 0.74);
}

.footer-contact-label {
  display: inline-block;
  min-width: 44px;
  margin-right: 8px;
  color: var(--cyan);
  letter-spacing: 0.14em;
}

/* ---------- 11. 通用容器与章节 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: clamp(40px, 6vw, 88px); }

.section-head {
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: 64ch;
  margin-bottom: clamp(20px, 3vw, 36px);
}

.eyebrow {
  font: 600 10px/1 var(--font-mono);
  letter-spacing: 0.26em;
  color: var(--cyan);
  max-width: none;
}

.section-title {
  font: 700 clamp(28px, 3.4vw, 48px)/1.12 var(--font-display);
  letter-spacing: -0.015em;
  color: var(--cream);
}

.lede {
  max-width: 68ch;
  font: 400 16px/1.75 var(--font-body);
  color: rgba(243, 237, 226, 0.78);
}

.display {
  font: 300 clamp(56px, 8vw, 132px)/0.98 var(--font-display);
  letter-spacing: -0.02em;
  color: var(--cream);
}

/* ---------- 12. 栅格与卡片 ---------- */
.grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 28px);
}

.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.card {
  position: relative;
  padding: clamp(20px, 2.4vw, 30px);
  background: rgba(12, 42, 64, 0.78);
  border: 2px solid var(--line);
  box-shadow: 6px 6px 0 rgba(3, 12, 18, 0.45);
  color: var(--cream);
  transition: transform 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.card:hover {
  transform: translate(-2px, -2px);
  border-color: rgba(24, 224, 207, 0.55);
  box-shadow: 8px 8px 0 rgba(3, 12, 18, 0.55);
}

.card-kicker {
  font: 600 10px/1 var(--font-mono);
  letter-spacing: 0.22em;
  color: var(--cyan);
  max-width: none;
}

.card-title {
  margin-top: 10px;
  font: 700 clamp(18px, 1.6vw, 22px)/1.3 var(--font-display);
  letter-spacing: 0;
  color: var(--cream);
}

.card-text {
  margin-top: 10px;
  max-width: 46ch;
  font: 400 14px/1.7 var(--font-body);
  color: rgba(185, 216, 212, 0.85);
}

/* ---------- 13. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 24px;
  background: transparent;
  color: var(--cyan);
  border: 2px solid currentColor;
  text-decoration: none;
  cursor: pointer;
  font: 700 14px/1 var(--font-display);
  letter-spacing: 0.08em;
  transition: transform 0.16s var(--ease), background 0.16s var(--ease), color 0.16s var(--ease), box-shadow 0.16s var(--ease), border-color 0.16s var(--ease);
}

.btn--primary {
  background: var(--cyan);
  color: #04161F;
  border-color: var(--coal);
  box-shadow: 5px 5px 0 rgba(3, 12, 18, 0.55);
}

.btn--primary:hover {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0 rgba(3, 12, 18, 0.6);
}

.btn--coral {
  background: var(--coral);
  color: #170703;
  border-color: var(--coal);
  box-shadow: 5px 5px 0 rgba(3, 12, 18, 0.55);
}

.btn--coral:hover {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0 rgba(3, 12, 18, 0.6);
  background: #FF8867;
}

.btn--ghost {
  color: var(--cyan-soft);
  border-color: rgba(140, 248, 238, 0.45);
}

.btn--ghost:hover {
  background: rgba(24, 224, 207, 0.12);
  border-color: var(--cyan);
}

.btn:active {
  transform: translate(1px, 1px);
  box-shadow: 2px 2px 0 rgba(3, 12, 18, 0.55);
}

/* ---------- 14. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 10px;
  border: 1px solid currentColor;
  font: 600 10px/1.2 var(--font-mono);
  letter-spacing: 0.14em;
  text-decoration: none;
  white-space: nowrap;
}

.tag--cyan {
  color: var(--cyan);
  background: rgba(24, 224, 207, 0.1);
}

.tag--coral {
  color: #170703;
  background: var(--coral);
  border-color: var(--coral);
}

.tag--moss {
  color: var(--mist);
  background: rgba(92, 122, 98, 0.34);
  border-color: rgba(92, 122, 98, 0.85);
}

/* ---------- 15. 面包屑 ---------- */
.breadcrumb {
  font: 500 11px/1.4 var(--font-mono);
  letter-spacing: 0.1em;
  color: rgba(185, 216, 212, 0.65);
}

.breadcrumb-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px;
  margin: 0;
  padding: 0;
}

.breadcrumb-list > li { display: inline-flex; align-items: baseline; }

.breadcrumb-list > li + li::before {
  content: "/";
  margin-right: 8px;
  color: rgba(24, 224, 207, 0.5);
}

.breadcrumb-link {
  color: inherit;
  text-decoration: none;
  transition: color 0.16s var(--ease);
}

.breadcrumb-link:hover { color: var(--cyan-soft); }

.breadcrumb-current { color: var(--cyan); }

/* ---------- 16. 图片容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 2px solid var(--line);
  background-image:
    radial-gradient(80% 80% at 78% 12%, rgba(24, 224, 207, 0.22), transparent 62%),
    linear-gradient(140deg, #0C2A40 0%, #163B4D 55%, #071C2C 100%);
}

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

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 4 / 5; }

.media-caption {
  margin-top: 10px;
  font: 500 11px/1.6 var(--font-mono);
  letter-spacing: 0.1em;
  color: rgba(185, 216, 212, 0.6);
  max-width: 60ch;
}

/* ---------- 17. 移动端：顶栏 + 抽屉 ---------- */
@media (max-width: 959px) {
  body {
    padding-left: 0;
    padding-top: var(--topbar-h);
    background-attachment: scroll;
  }

  body.nav-open { overflow: hidden; }

  .site-header {
    top: 0;
    left: 0;
    right: 0;
    bottom: auto;
    width: 100%;
    height: var(--topbar-h);
    border-right: 0;
    border-bottom: 2px solid rgba(24, 224, 207, 0.28);
    background: linear-gradient(180deg, #071C2C 0%, #0C2A40 100%);
  }

  .rail-inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding: 0 var(--gutter);
    overflow: visible;
  }

  .rail-head {
    width: 100%;
    justify-content: flex-start;
  }

  .rail-descriptor,
  .rail-foot { display: none; }

  .nav-toggle {
    position: fixed;
    top: 11px;
    right: 14px;
    z-index: 120;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: rgba(7, 28, 44, 0.82);
    color: var(--cyan);
    border: 2px solid rgba(24, 224, 207, 0.45);
    cursor: pointer;
    font: 600 11px/1 var(--font-mono);
    letter-spacing: 0.14em;
    transition: color 0.18s var(--ease), border-color 0.18s var(--ease), background 0.18s var(--ease);
  }

  .nav-toggle:hover {
    border-color: var(--cyan);
    color: var(--cyan-soft);
  }

  .site-header[data-open] .nav-toggle-bar:first-child {
    transform: translateY(3px) rotate(45deg);
  }

  .site-header[data-open] .nav-toggle-bar:last-child {
    transform: translateY(-3px) rotate(-45deg);
  }

  .site-nav {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    z-index: 95;
    width: min(86vw, 348px);
    padding: calc(var(--topbar-h) + 20px) 20px 30px;
    overflow-y: auto;
    overscroll-behavior: contain;
    background: linear-gradient(180deg, #0C2A40 0%, #071C2C 68%, #163B4D 100%);
    border-left: 2px solid var(--cyan);
    box-shadow: -18px 0 48px rgba(2, 10, 16, 0.62);
    transform: translateX(102%);
    transition: transform 0.32s var(--ease);
  }

  .site-header[data-open] .site-nav {
    transform: translateX(0);
  }

  .nav-link {
    padding: 13px 12px;
    font-size: 15px;
  }

  .nav-scrim {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 88;
    background: rgba(3, 12, 18, 0.62);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s var(--ease);
  }

  .site-header[data-open] + .nav-scrim {
    opacity: 1;
    pointer-events: auto;
  }

  .rail-progress {
    top: auto;
    bottom: 0;
    left: 0;
    right: 0;
    width: 100%;
    height: 3px;
  }

  .rail-progress-bar {
    transform: scaleX(var(--progress, 0));
    transform-origin: left center;
  }

  .footer-feedback {
    grid-template-columns: 1fr;
    align-items: start;
  }

  .footer-feedback-link { justify-self: start; }

  .footer-meta {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 860px) {
  .grid-2,
  .grid-3 { grid-template-columns: 1fr; }

  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px 20px;
  }
}

@media (max-width: 520px) {
  .footer-grid { grid-template-columns: 1fr; }

  .display { font-size: clamp(42px, 13vw, 64px); }

  .brand-name { font-size: 15px; }

  .nav-toggle-label { display: none; }
}

/* ---------- 18. 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}