/* ============================================================
   视讯网投会馆 · 共享站控样式表  /assets/site.css
   夜间蓝图会馆：左侧轨道 + 深靛蓝分区 + 霓虹青锚点
   ============================================================ */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  background: #06101F;
  scroll-behavior: smooth;
}

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

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

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

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

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

/* ---------- 2. 设计令牌 ---------- */
:root {
  /* 色板 */
  --ink-900: #06101F;
  --ink-850: #08152A;
  --ink-800: #0B1C36;
  --ink-700: #12294A;
  --line: #2E4C70;
  --line-soft: rgba(46, 76, 112, .55);
  --paper: #F4F7FB;
  --paper-dim: rgba(244, 247, 251, .74);
  --muted: #8FA6C0;
  --cyan: #35E6D4;
  --amber: #F5B45B;
  --violet: #9B8AC4;
  --coral: #FF7A6B;

  /* 字体 */
  --font-display: "Sora", "Space Grotesk", "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, sans-serif;
  --font-mono: "Space Grotesk", ui-monospace, SFMono-Regular, Menlo, Consolas, "Courier New", monospace;

  /* 结构 */
  --rail-w: 280px;
  --header-h: 62px;
  --maxw: 1180px;
  --radius: 18px;
  --radius-sm: 12px;
  --radius-cut: 12px 4px 12px 4px;

  /* 质感 */
  --shadow-panel: 0 22px 50px -34px rgba(0, 0, 0, .92);
  --glow-cyan: 0 0 22px rgba(53, 230, 212, .32);
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ---------- 3. 基底与中文排版 ---------- */
body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: .012em;
  color: var(--paper);
  background:
    radial-gradient(920px 640px at 86% -14%, rgba(53, 230, 212, .10), transparent 62%),
    radial-gradient(760px 560px at 2% 108%, rgba(155, 138, 196, .14), transparent 60%),
    var(--ink-900);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -.03em;
  line-height: 1.12;
  color: var(--paper);
}

h1 { font-size: clamp(34px, 5.2vw, 64px); }
h2 { font-size: clamp(26px, 3.4vw, 40px); }
h3 { font-size: clamp(19px, 2vw, 24px); letter-spacing: -.02em; }

::selection { background: var(--cyan); color: #03151C; }

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

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* ---------- 4. 跳过链接与主内容锚点 ---------- */
.skip-link {
  position: fixed;
  top: -90px;
  left: 16px;
  z-index: 999;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: 999px;
  background: var(--cyan);
  color: #03151C;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 14px;
  box-shadow: var(--glow-cyan);
  transition: top .22s var(--ease);
}
.skip-link:focus { top: 14px; }

#main-content {
  display: block;
  scroll-margin-top: calc(var(--header-h) + 28px);
}

/* ---------- 5. 头部：移动端顶栏 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: var(--header-h);
  padding: 8px clamp(16px, 4vw, 26px);
  color: var(--paper);
  background: rgba(6, 16, 31, .94);
  border-bottom: 1px solid var(--line-soft);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
}

.rail-head {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex: 1 1 auto;
  width: 100%;
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  min-width: 0;
}

.brand-mark {
  position: relative;
  flex: none;
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: var(--radius-cut);
  background:
    radial-gradient(circle at 30% 26%, rgba(53, 230, 212, .34), transparent 64%),
    var(--ink-700);
  transition: border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.brand:hover .brand-mark {
  border-color: rgba(53, 230, 212, .72);
  box-shadow: var(--glow-cyan);
}

.brand-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 12px var(--cyan);
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.brand-name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 16px;
  line-height: 1.2;
  letter-spacing: -.02em;
  color: var(--paper);
  white-space: nowrap;
}

.brand-tag {
  font-family: var(--font-mono);
  font-size: 9px;
  line-height: 1.4;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--muted);
  white-space: nowrap;
}

/* 移动导航按钮 */
.nav-toggle {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-cut);
  background: rgba(18, 41, 74, .72);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  cursor: pointer;
  transition: border-color .25s var(--ease), color .25s var(--ease), background .25s var(--ease);
}
.nav-toggle:hover {
  border-color: rgba(53, 230, 212, .6);
  color: var(--cyan);
  background: rgba(18, 41, 74, .95);
}

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 16px;
  height: 10px;
}
.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 1.5px;
  border-radius: 2px;
  background: currentColor;
  transform-origin: center;
  transition: top .28s var(--ease), transform .28s var(--ease);
}
.nav-toggle-bars::before { top: 0; }
.nav-toggle-bars::after { top: 8px; }

.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before {
  top: 4px;
  transform: rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after {
  top: 4px;
  transform: rotate(-45deg);
}

.nav-toggle-label {
  font-size: 11px;
  line-height: 1;
}

/* ---------- 6. 导航：移动抽屉 ---------- */
.site-nav {
  position: fixed;
  top: var(--header-h);
  right: 0;
  bottom: 0;
  z-index: 120;
  display: flex;
  flex-direction: column;
  gap: 20px;
  width: min(86vw, 340px);
  padding: 26px 22px 34px;
  overflow-y: auto;
  overscroll-behavior: contain;
  background: linear-gradient(180deg, var(--ink-800), var(--ink-900));
  border-left: 1px solid var(--line-soft);
  box-shadow: -30px 0 70px -40px rgba(0, 0, 0, .95);
  transform: translateX(104%);
  visibility: hidden;
  transition: transform .34s var(--ease), visibility .34s var(--ease);
}
.site-nav[data-open] {
  transform: translateX(0);
  visibility: visible;
}

.nav-eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--muted);
}
.nav-eyebrow::after {
  content: "";
  flex: 1 1 auto;
  height: 1px;
  background: linear-gradient(90deg, var(--line), transparent);
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 12px;
  border: 1px solid transparent;
  border-radius: var(--radius-cut);
  color: var(--paper-dim);
  font-size: 14px;
  letter-spacing: .02em;
  transition: color .22s var(--ease), background .22s var(--ease), border-color .22s var(--ease);
}

.nav-num {
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: .08em;
  color: var(--line);
  transition: color .22s var(--ease);
}

.nav-label { white-space: nowrap; }

.nav-link:hover {
  color: var(--paper);
  background: rgba(18, 41, 74, .74);
  border-color: var(--line-soft);
}
.nav-link:hover .nav-num { color: var(--violet); }

.nav-link[aria-current="page"] {
  color: var(--paper);
  font-weight: 700;
  background: linear-gradient(100deg, rgba(53, 230, 212, .17), rgba(53, 230, 212, .04));
  border-color: rgba(53, 230, 212, .5);
  box-shadow: inset 2px 0 0 var(--cyan);
}
.nav-link[aria-current="page"] .nav-num { color: var(--cyan); }
.nav-link[aria-current="page"]:hover {
  background: linear-gradient(100deg, rgba(53, 230, 212, .24), rgba(53, 230, 212, .07));
}

.rail-actions {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.rail-meta {
  display: flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted);
}
.rail-coord { color: var(--cyan); }
.rail-dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 8px var(--amber);
}

/* ---------- 7. 桌面端：左侧轨道 ---------- */
@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }

  #main-content { scroll-margin-top: 36px; }

  .site-header {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    width: var(--rail-w);
    min-height: 0;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 24px 22px 20px;
    overflow-y: auto;
    overscroll-behavior: contain;
    border-bottom: 0;
    border-right: 1px solid var(--line-soft);
    background: linear-gradient(180deg, var(--ink-800), var(--ink-900) 74%);
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }

  .site-header::before {
    content: "";
    position: absolute;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    opacity: .85;
    background-image:
      linear-gradient(90deg, rgba(46, 76, 112, .30) 1px, transparent 1px),
      linear-gradient(180deg, rgba(46, 76, 112, .22) 1px, transparent 1px);
    background-size: 28px 28px;
    -webkit-mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, .28) 60%, transparent 92%);
    mask-image: linear-gradient(180deg, #000 0%, rgba(0, 0, 0, .28) 60%, transparent 92%);
  }

  .rail-head {
    flex: 0 0 auto;
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    gap: 0;
  }

  .nav-toggle { display: none; }

  .brand-name { font-size: 17px; }

  .site-nav {
    position: relative;
    top: auto;
    right: auto;
    bottom: auto;
    z-index: 1;
    flex: 1 1 auto;
    width: auto;
    margin-top: 28px;
    padding: 0;
    overflow: visible;
    background: transparent;
    border-left: 0;
    box-shadow: none;
    transform: none;
    visibility: visible;
    transition: none;
  }

  .rail-actions {
    margin-top: auto;
    padding-top: 24px;
  }

  .rail-meta {
    margin-top: 16px;
    padding-top: 14px;
    border-top: 1px solid var(--line-soft);
  }
}

/* ---------- 8. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 18px;
  border: 1px solid transparent;
  border-radius: var(--radius-cut);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 14px;
  line-height: 1.1;
  letter-spacing: .03em;
  text-align: center;
  cursor: pointer;
  transition: transform .22s var(--ease), background .22s var(--ease),
              border-color .22s var(--ease), color .22s var(--ease),
              box-shadow .22s var(--ease);
}

.btn-primary {
  background: var(--cyan);
  color: #03151C;
  box-shadow: 0 14px 30px -18px rgba(53, 230, 212, .95);
}
.btn-primary:hover {
  background: #61F1E4;
  transform: translateY(-1px);
  box-shadow: 0 18px 34px -16px rgba(53, 230, 212, .9);
}
.btn-primary:active { transform: translateY(0); }

.btn-ghost {
  background: transparent;
  color: var(--amber);
  border-color: rgba(245, 180, 91, .46);
}
.btn-ghost:hover {
  background: rgba(245, 180, 91, .12);
  border-color: var(--amber);
  transform: translateY(-1px);
}

.btn-sm {
  padding: 9px 14px;
  font-size: 12.5px;
  border-radius: 10px 3px 10px 3px;
}

/* ---------- 9. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 7vw, 96px);
  padding-top: clamp(40px, 5vw, 64px);
  color: var(--paper);
  background: linear-gradient(180deg, rgba(8, 21, 42, .55), var(--ink-900) 46%);
  border-top: 1px solid var(--line-soft);
}
.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(53, 230, 212, .65), rgba(245, 180, 91, .5), transparent);
}

.footer-grid {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 clamp(20px, 4vw, 44px);
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 46px);
}

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

.footer-mark {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 19px;
  letter-spacing: -.02em;
  color: var(--paper);
}
.footer-mark::before {
  content: "";
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  background: var(--cyan);
  box-shadow: 0 0 12px rgba(53, 230, 212, .9);
}

.footer-line {
  margin: 0 0 10px;
  max-width: 24ch;
  font-size: 13px;
  line-height: 1.85;
  color: var(--muted);
}

.footer-note {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .1em;
  color: rgba(143, 166, 192, .88);
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 14px;
  min-width: 0;
}

.footer-title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--violet);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  align-self: flex-start;
  padding-bottom: 1px;
  font-size: 13.5px;
  color: var(--paper-dim);
  border-bottom: 1px solid transparent;
  transition: color .22s var(--ease), border-color .22s var(--ease);
}
.footer-link::before {
  content: "";
  width: 5px;
  height: 1px;
  background: var(--line);
  transition: width .22s var(--ease), background .22s var(--ease);
}
.footer-link:hover {
  color: var(--cyan);
  border-bottom-color: rgba(53, 230, 212, .5);
}
.footer-link:hover::before {
  width: 12px;
  background: var(--cyan);
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 14px;
  min-width: 0;
}

.contact-row {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.contact-label {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--muted);
}

.contact-value {
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--paper);
  word-break: break-word;
}

.footer-base {
  width: 100%;
  max-width: var(--maxw);
  margin: clamp(34px, 5vw, 56px) auto 0;
  padding: 16px clamp(20px, 4vw, 44px) 26px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 22px;
  border-top: 1px solid var(--line-soft);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--muted);
}

.footer-legal {
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer-sep { color: var(--line); }

.footer-region {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--amber);
}
.footer-region::before {
  content: "";
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 8px var(--amber);
}

.footer-copy { margin: 0; }

/* ---------- 10. 通用布局 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: clamp(20px, 4vw, 44px);
}
.container--narrow { max-width: 860px; }

.grid {
  display: grid;
  gap: clamp(16px, 2vw, 26px);
}
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); }

/* ---------- 11. 基础组件 ---------- */
.breadcrumb { margin-bottom: clamp(20px, 3vw, 34px); }

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
}
.breadcrumb-list li {
  display: flex;
  align-items: center;
  gap: 8px;
}
.breadcrumb-list li + li::before {
  content: "/";
  color: var(--line);
}
.breadcrumb-link {
  color: var(--muted);
  border-bottom: 1px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}
.breadcrumb-link:hover {
  color: var(--cyan);
  border-bottom-color: currentColor;
}
.breadcrumb-current { color: var(--paper); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--cyan);
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: currentColor;
}

.section-title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -.03em;
  line-height: 1.1;
  font-size: clamp(24px, 3vw, 40px);
  color: var(--paper);
}

.lede {
  max-width: 44ch;
  font-size: clamp(15px, 1.4vw, 17px);
  line-height: 1.8;
  color: var(--paper-dim);
  text-wrap: pretty;
}

.panel {
  position: relative;
  padding: clamp(18px, 2.4vw, 28px);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--ink-800), var(--ink-850));
  box-shadow: var(--shadow-panel);
}
.panel--glow {
  border-color: rgba(53, 230, 212, .42);
  box-shadow: 0 0 0 1px rgba(53, 230, 212, .12), var(--shadow-panel);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 11px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(18, 41, 74, .62);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--paper-dim);
}
.tag--cyan {
  border-color: rgba(53, 230, 212, .45);
  color: var(--cyan);
}
.tag--amber {
  border-color: rgba(245, 180, 91, .45);
  color: var(--amber);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.stat-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(28px, 3.4vw, 44px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--paper);
}
.stat-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
}

.media-frame {
  position: relative;
  overflow: hidden;
  isolation: isolate;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: var(--ink-700);
}
.media-frame img,
.media-frame svg,
.media-frame video {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, transparent 44%, rgba(6, 16, 31, .86));
}
.media-frame--plain::after { display: none; }
.media-frame--16x9 { aspect-ratio: 16 / 9; }
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }

.media-caption {
  margin: 10px 0 0;
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--muted);
}

.prose {
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--paper-dim);
}
.prose > * + * { margin-top: 1.1em; }
.prose h2 {
  margin-top: 1.8em;
  font-size: clamp(22px, 2.4vw, 30px);
  color: var(--paper);
}
.prose h3 {
  margin-top: 1.5em;
  font-size: clamp(18px, 1.8vw, 22px);
  color: var(--paper);
}
.prose p,
.prose li { text-wrap: pretty; }
.prose a {
  color: var(--cyan);
  border-bottom: 1px solid rgba(53, 230, 212, .4);
}
.prose a:hover { border-bottom-color: var(--cyan); }
.prose ul,
.prose ol {
  padding-left: 1.2em;
  list-style: disc;
}
.prose ol { list-style: decimal; }
.prose li + li { margin-top: .4em; }

/* ---------- 12. 浏览辅助（JS 注入） ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  z-index: 140;
  pointer-events: none;
}
.scroll-progress__bar {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--cyan), var(--amber));
  box-shadow: 0 0 14px rgba(53, 230, 212, .65);
  transition: width .12s linear;
}

.to-top {
  position: fixed;
  right: clamp(16px, 3vw, 32px);
  bottom: clamp(16px, 3vw, 32px);
  z-index: 130;
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  padding: 0;
  border: 1px solid rgba(53, 230, 212, .45);
  border-radius: var(--radius-cut);
  background: rgba(11, 28, 54, .9);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  transition: opacity .26s var(--ease), transform .26s var(--ease),
              visibility .26s var(--ease), background .22s var(--ease),
              box-shadow .22s var(--ease);
}
.to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.to-top:hover {
  background: rgba(53, 230, 212, .18);
  box-shadow: var(--glow-cyan);
}

/* ---------- 13. 响应式补强 ---------- */
@media (min-width: 560px) {
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-brand { grid-column: 1 / -1; }
}

@media (min-width: 720px) {
  .footer-base { font-size: 11.5px; }
}

@media (min-width: 1180px) {
  .footer-grid { grid-template-columns: 1.5fr .8fr .8fr .9fr 1.35fr; }
  .footer-brand { grid-column: auto; }
}

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

@media (max-width: 380px) {
  .brand-tag { display: none; }
  .nav-toggle-label { display: none; }
}

/* ---------- 14. 减少动态效果 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }

  .site-nav { transition: none; }
  .scroll-progress__bar { transition: none; }
  .skip-link { transition: none; }
}