/* ============================================================
   使用教程网站 · 样式表
   设计语言：极夜 / 极光 —— 深青夜色 + 极光青辉（基于 JIYEX）
   ============================================================ */

:root {
  --bg: #f5f7fa;
  --bg-alt: #eef1f5;
  --card-bg: #ffffff;
  --card-bg-alt: #f8fafc;
  --text: #1a1a2e;
  --text-muted: #5c6b7a;
  --text-faint: #8a9aa8;
  --line: rgba(0, 0, 0, .08);
  --line-soft: rgba(0, 0, 0, .04);
  --teal: #0d9488;
  --teal-deep: #0f766e;
  --teal-bright: #14b8a6;
  --teal-dim: #5eead4;
  --ink: #1a1a2e;
  --muted: #5c6b7a;
  --faint: #8a9aa8;
  --night-0: #f5f7fa;
  --night-1: #eef1f5;
  --night-2: #e2e6ed;
  --night-3: #d1d7e0;
  --sidebar-w: 280px;
  --ease-long: cubic-bezier(.16, 1, .3, 1);
  --ease-soft: cubic-bezier(.25, .8, .25, 1);
  --t-hover: .55s;
  --serif: "Noto Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --sans: "Noto Sans SC", "Microsoft YaHei", "PingFang SC", sans-serif;
}

.dark-mode {
  --night-0: #071316;
  --night-1: #0b1c20;
  --night-2: #11262a;
  --night-3: #16343a;
  --teal: #58beb4;
  --teal-deep: #087a76;
  --teal-bright: #8fe6da;
  --teal-dim: #4faaa2;
  --ink: #e9f4f1;
  --muted: #9eb2b5;
  --faint: #7d959b;
  --line: rgba(88, 190, 180, .14);
  --line-soft: rgba(88, 190, 180, .08);
  --bg: var(--night-0);
  --bg-alt: var(--night-1);
  --card-bg: var(--night-1);
  --card-bg-alt: var(--night-2);
  --text: var(--ink);
  --text-muted: var(--muted);
  --text-faint: var(--faint);
}

.dark-mode .sky { display: block; }
.dark-mode .sky-light { display: none; }

* { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.75;
  min-width: 320px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  transition: background .6s var(--ease-soft), color .6s var(--ease-soft);
}

::selection { background: rgba(20, 184, 166, .28); color: #fff; }
.dark-mode ::selection { background: rgba(88, 190, 180, .28); color: #fff; }

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; height: auto; }
ol, ul { list-style: none; }

a:focus-visible, button:focus-visible {
  outline: 1.5px solid var(--teal);
  outline-offset: 4px;
}

/* ===== 背景 ===== */
.sky { display: none; }
.sky-light {
  display: block;
  position: fixed; inset: 0; z-index: -1;
  overflow: hidden; pointer-events: none;
  background: linear-gradient(175deg, #f0f4f8 0%, #e2e8f0 40%, #dce3ec 100%);
}
.sky-light::after {
  content: "";
  position: absolute;
  top: -20%; right: -10%;
  width: 70%; height: 70%;
  background: radial-gradient(circle at 50% 50%, rgba(20, 184, 166, .06) 0%, transparent 70%);
  filter: blur(30px);
}
.sky {
  position: fixed; inset: 0; z-index: -1;
  overflow: hidden; pointer-events: none;
}
.sky-night {
  position: absolute; inset: 0;
  background:
    radial-gradient(120% 90% at 78% -10%, rgba(18, 79, 82, .55) 0%, transparent 55%),
    radial-gradient(100% 80% at 8% 110%, rgba(8, 60, 63, .5) 0%, transparent 55%),
    linear-gradient(178deg, #081619 0%, var(--night-0) 42%, #060f12 100%);
}
.aurora {
  position: absolute;
  width: 130vmax; height: 42vmax;
  filter: blur(64px); opacity: .5;
  will-change: transform;
}
.aurora-a {
  top: -18vmax; left: -22vmax;
  background: conic-gradient(from 120deg at 50% 50%,
    transparent 0deg, rgba(8, 122, 118, .34) 60deg,
    rgba(88, 190, 180, .16) 110deg, transparent 170deg,
    rgba(18, 79, 82, .3) 250deg, transparent 320deg);
  animation: aurora-drift-a 46s var(--ease-soft) infinite alternate;
}
.aurora-b {
  top: 6vmax; right: -46vmax;
  background: conic-gradient(from 300deg at 50% 50%,
    transparent 0deg, rgba(79, 170, 162, .26) 70deg,
    rgba(8, 122, 118, .34) 140deg, transparent 210deg,
    rgba(88, 190, 180, .12) 300deg, transparent 360deg);
  animation: aurora-drift-b 62s var(--ease-soft) infinite alternate;
}
.aurora-c {
  bottom: -30vmax; left: -12vmax; opacity: .34;
  background: conic-gradient(from 200deg at 50% 50%,
    transparent 0deg, rgba(18, 79, 82, .4) 80deg,
    rgba(88, 190, 180, .14) 150deg, transparent 220deg,
    rgba(8, 60, 63, .4) 300deg, transparent 360deg);
  animation: aurora-drift-c 54s var(--ease-soft) infinite alternate;
}
@keyframes aurora-drift-a {
  0%   { transform: translate3d(0, var(--py, 0px), 0) rotate(-4deg) scale(1); }
  100% { transform: translate3d(9vmax, calc(4vmax + var(--py, 0px)), 0) rotate(7deg) scale(1.14); }
}
@keyframes aurora-drift-b {
  0%   { transform: translate3d(0, var(--py, 0px), 0) rotate(6deg) scale(1.08); }
  100% { transform: translate3d(-10vmax, calc(-3vmax + var(--py, 0px)), 0) rotate(-6deg) scale(1); }
}
@keyframes aurora-drift-c {
  0%   { transform: translate3d(0, var(--py, 0px), 0) rotate(0deg) scale(1); }
  100% { transform: translate3d(6vmax, calc(-5vmax + var(--py, 0px)), 0) rotate(9deg) scale(1.18); }
}
.sky-chart {
  position: absolute; inset: -2%;
  background-image:
    radial-gradient(circle at 18% 22%, rgba(143, 230, 218, .5) 0, 1px, transparent 1.6px),
    radial-gradient(circle at 66% 12%, rgba(143, 230, 218, .35) 0, 1px, transparent 1.6px),
    radial-gradient(circle at 84% 38%, rgba(143, 230, 218, .4) 0, 1px, transparent 1.6px),
    radial-gradient(circle at 34% 64%, rgba(143, 230, 218, .3) 0, 1px, transparent 1.6px),
    radial-gradient(circle at 8% 82%, rgba(143, 230, 218, .35) 0, 1px, transparent 1.6px),
    radial-gradient(circle at 52% 88%, rgba(143, 230, 218, .28) 0, 1px, transparent 1.6px),
    linear-gradient(rgba(88, 190, 180, .05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(88, 190, 180, .05) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 100% 100%, 100% 100%, 100% 100%, 100% 100%, 72px 72px, 72px 72px;
  mask-image: radial-gradient(90% 70% at 50% 30%, #000 30%, transparent 78%);
  -webkit-mask-image: radial-gradient(90% 70% at 50% 30%, #000 30%, transparent 78%);
  animation: chart-breathe 12s ease-in-out infinite alternate;
}
@keyframes chart-breathe { from { opacity: .55; } to { opacity: 1; } }
.sky-grain {
  position: absolute; inset: 0; opacity: .05; mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='240' height='240'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ===== 滚动进度条 ===== */
.scroll-progress {
  position: fixed; top: 0; left: 0; right: 0;
  height: 2px; z-index: 70; background: transparent;
}
.scroll-progress i {
  display: block; height: 100%;
  background: linear-gradient(90deg, var(--teal-deep), var(--teal-bright));
  transform-origin: 0 50%; transform: scaleX(0);
  transition: transform .18s linear;
}

/* ===== 页头 ===== */
.site-head {
  position: fixed; top: 0; left: 0; right: 0; z-index: 60;
  transition: background var(--t-hover) var(--ease-soft),
              border-color var(--t-hover) var(--ease-soft),
              backdrop-filter var(--t-hover) var(--ease-soft);
  border-bottom: 1px solid transparent;
}
.site-head.scrolled {
  background: rgba(245, 247, 250, .8);
  -webkit-backdrop-filter: blur(18px) saturate(1.3);
  backdrop-filter: blur(18px) saturate(1.3);
  border-bottom-color: var(--line-soft);
}
.dark-mode .site-head.scrolled {
  background: rgba(7, 19, 22, .72);
}
.head-inner {
  max-width: 1360px;
  margin: 0 auto;
  padding: 0 40px;
  height: 72px;
  display: flex;
  align-items: center;
  gap: 32px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: none;
  color: var(--teal);
}
.brand-mark { width: 52px; height: 52px; border-radius: 10px; }
.brand-word b {
  display: block;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: .12em;
  color: var(--text);
  line-height: 1.2;
  transition: color .5s var(--ease-soft);
}
.brand-word small {
  display: block;
  font-size: 9px;
  letter-spacing: .28em;
  color: var(--text-faint);
  margin-top: 1px;
}
.head-nav {
  flex: 1;
  display: flex;
  justify-content: center;
  gap: 32px;
}
.head-nav a {
  position: relative;
  font-size: 13px;
  color: var(--text-muted);
  letter-spacing: .06em;
  padding: 6px 2px;
  transition: color var(--t-hover) var(--ease-soft);
}
.head-nav a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 1px;
  background: var(--teal);
  transform: scaleX(0);
  transform-origin: 100% 50%;
  transition: transform .7s var(--ease-long);
}
.head-nav a:hover { color: var(--text); }
.head-nav a:hover::after { transform: scaleX(1); transform-origin: 0 50%; }
.head-actions { display: flex; align-items: center; gap: 18px; flex: none; }

.theme-toggle {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--card-bg);
  color: var(--text-muted);
  cursor: pointer;
  transition: background .5s var(--ease-soft), color .5s var(--ease-soft),
              border-color .5s var(--ease-soft), transform .5s var(--ease-long);
  flex: none;
}
.theme-toggle:hover {
  color: var(--teal); border-color: var(--teal); transform: translateY(-1px);
}
.theme-toggle svg { width: 18px; height: 18px; position: absolute; transition: opacity .5s var(--ease-soft), transform .5s var(--ease-soft); }
.theme-toggle .icon-sun { opacity: 1; transform: rotate(0deg) scale(1); }
.theme-toggle .icon-moon { opacity: 0; transform: rotate(90deg) scale(0); }
.dark-mode .theme-toggle .icon-sun { opacity: 0; transform: rotate(-90deg) scale(0); }
.dark-mode .theme-toggle .icon-moon { opacity: 1; transform: rotate(0deg) scale(1); }

/* ===== 布局 ===== */
.layout {
  display: flex;
  padding-top: 72px;
  min-height: 100vh;
}

/* ===== 侧边栏 ===== */
.sidebar {
  position: fixed;
  top: 72px; left: 0; bottom: 0;
  width: var(--sidebar-w);
  background: var(--card-bg);
  border-right: 1px solid var(--line-soft);
  overflow-y: auto;
  z-index: 40;
  transition: background .5s var(--ease-soft), border-color .5s var(--ease-soft);
  padding: 28px 0 40px;
}
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--line); border-radius: 3px; }
.sidebar::-webkit-scrollbar-track { background: transparent; }
.sidebar-section { margin-bottom: 24px; }
.sidebar-label {
  display: block;
  padding: 0 24px;
  font-size: 10.5px;
  letter-spacing: .12em;
  color: var(--text-faint);
  font-weight: 500;
  margin-bottom: 10px;
  text-transform: uppercase;
}
.sidebar-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 24px;
  font-size: 13.5px;
  color: var(--text-muted);
  transition: all .4s var(--ease-soft);
  border-left: 2px solid transparent;
}
.sidebar-link:hover {
  color: var(--text);
  background: var(--bg-alt);
}
.sidebar-link.active {
  color: var(--teal);
  border-left-color: var(--teal);
  background: rgba(13, 148, 136, .06);
}
.dark-mode .sidebar-link.active {
  background: rgba(88, 190, 180, .08);
}
.sidebar-link .icon {
  width: 16px; height: 16px; flex: none;
  opacity: .6; color: var(--text-faint);
}
.sidebar-link.active .icon { opacity: 1; color: var(--teal); }
.sidebar-divider {
  margin: 16px 24px;
  border: none;
  height: 1px;
  background: var(--line-soft);
}

/* ===== 主内容 ===== */
.main-content {
  margin-left: var(--sidebar-w);
  flex: 1;
  padding: 60px 64px 100px;
  max-width: calc(100% - var(--sidebar-w));
}

/* ===== 面包屑 ===== */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--text-faint);
  margin-bottom: 24px;
}
.breadcrumb a { color: var(--text-muted); transition: color .3s; }
.breadcrumb a:hover { color: var(--teal); }
.breadcrumb .sep { opacity: .4; }

/* ===== 内容排版 ===== */
.content h1 {
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(28px, 3.2vw, 38px);
  line-height: 1.3;
  letter-spacing: .04em;
  color: var(--text);
  margin-bottom: 16px;
}
.content .lead {
  color: var(--text-muted);
  font-size: 15.5px;
  max-width: 640px;
  margin-bottom: 48px;
}
.content h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 24px;
  color: var(--text);
  margin: 48px 0 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-soft);
}
.content h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 18px;
  color: var(--text);
  margin: 32px 0 12px;
}
.content p {
  margin-bottom: 18px;
  color: var(--text-muted);
}
.content p strong { color: var(--text); font-weight: 500; }
.content code:not(.code-block code) {
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  font-size: .92em;
  padding: 2px 8px;
  background: var(--bg-alt);
  border-radius: 3px;
  color: var(--teal-deep);
}
.dark-mode .content code:not(.code-block code) { color: var(--teal-bright); }

/* ===== 卡片 ===== */
.card {
  background: var(--card-bg);
  border: 1px solid var(--line-soft);
  border-radius: 6px;
  padding: 28px 32px;
  margin: 24px 0;
  transition: background .5s var(--ease-soft), border-color .5s var(--ease-soft);
}
.card-title {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 16px;
  color: var(--text);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.card-title .badge {
  display: inline-block;
  font-family: var(--sans);
  font-size: 10px;
  font-weight: 500;
  padding: 2px 10px;
  border-radius: 10px;
  background: rgba(13, 148, 136, .12);
  color: var(--teal);
  letter-spacing: .04em;
}
.dark-mode .card-title .badge { background: rgba(88, 190, 180, .15); }

/* ===== 步骤列表 ===== */
.steps { counter-reset: step; }
.step-item {
  position: relative;
  counter-increment: step;
  padding: 0 0 32px 44px;
  border-left: 1.5px solid var(--line);
  margin-left: 12px;
  transition: border-color .5s var(--ease-soft);
}
.step-item:last-child { border-left-color: transparent; padding-bottom: 0; }
.step-item::before {
  content: counter(step);
  position: absolute; left: -14px; top: 0;
  width: 26px; height: 26px;
  border-radius: 50%;
  background: var(--teal-deep);
  color: #f2fbfa;
  font-size: 12px;
  font-weight: 600;
  display: flex; align-items: center; justify-content: center;
}
.dark-mode .step-item::before { background: var(--teal); color: var(--night-0); }
.step-item h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 16px;
  color: var(--text);
  margin-bottom: 6px;
}
.step-item p { color: var(--text-muted); font-size: 14px; margin-bottom: 0; }

/* ===== 代码块 ===== */
.code-block {
  background: var(--bg-alt);
  border: 1px solid var(--line-soft);
  border-radius: 4px;
  margin: 20px 0;
  overflow: hidden;
  transition: background .5s var(--ease-soft), border-color .5s var(--ease-soft);
}
.code-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 16px;
  background: var(--card-bg);
  border-bottom: 1px solid var(--line-soft);
  font-size: 11.5px;
  color: var(--text-faint);
}
.code-header .lang { font-weight: 500; color: var(--teal-dim); }
.copy-btn {
  background: none; border: none;
  color: var(--text-faint); cursor: pointer;
  font-size: 11px; padding: 2px 8px; border-radius: 3px;
  transition: color .3s, background .3s;
  display: flex; align-items: center; gap: 4px;
}
.copy-btn:hover { color: var(--teal); background: var(--bg-alt); }
.code-block pre {
  padding: 16px 20px;
  overflow-x: auto;
  font-family: "SF Mono", "Cascadia Code", "Fira Code", "Consolas", monospace;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text);
}
.code-block code { font-family: inherit; }
.code-block pre::-webkit-scrollbar { height: 4px; }
.code-block pre::-webkit-scrollbar-thumb { background: var(--line); border-radius: 2px; }

/* ===== 提示框 ===== */
.tip {
  display: flex; gap: 14px;
  padding: 18px 22px;
  border-radius: 4px;
  margin: 20px 0;
  font-size: 14px;
  border-left: 3px solid;
}
.tip-info {
  background: rgba(13, 148, 136, .06);
  border-color: var(--teal);
  color: var(--text-muted);
}
.dark-mode .tip-info { background: rgba(88, 190, 180, .06); }
.tip-warn {
  background: rgba(245, 158, 11, .08);
  border-color: #f59e0b;
  color: var(--text-muted);
}
.tip-icon { font-size: 18px; flex: none; line-height: 1.5; }
.tip-info .tip-icon { color: var(--teal); }
.tip-warn .tip-icon { color: #f59e0b; }

/* ===== 表格 ===== */
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
  font-size: 14px;
}
.content th, .content td {
  padding: 10px 16px;
  text-align: left;
  border-bottom: 1px solid var(--line-soft);
}
.content th {
  font-weight: 600;
  color: var(--text);
  background: var(--bg-alt);
  font-size: 12.5px;
  letter-spacing: .06em;
}
.content td { color: var(--text-muted); }
.content tr:last-child td { border-bottom: none; }

/* ===== 标签 ===== */
.tag-list { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0; }
.tag {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 4px 12px; font-size: 12px;
  border-radius: 14px;
  background: var(--bg-alt);
  color: var(--text-muted);
  border: 1px solid var(--line-soft);
  transition: all .3s var(--ease-soft);
}
.tag:hover { border-color: var(--teal); color: var(--teal); }
.tag.tag-primary {
  background: rgba(13, 148, 136, .1);
  color: var(--teal); border-color: transparent;
}
.dark-mode .tag.tag-primary { background: rgba(88, 190, 180, .12); }

/* ===== TOC ===== */
.toc-card {
  background: var(--card-bg);
  border: 1px solid var(--line-soft);
  border-radius: 6px;
  padding: 24px 28px;
  margin: 32px 0;
}
.toc-title {
  font-size: 13px; font-weight: 600;
  color: var(--text-faint);
  letter-spacing: .1em;
  margin-bottom: 14px;
  text-transform: uppercase;
}
.toc-list { display: flex; flex-direction: column; gap: 6px; }
.toc-link {
  font-size: 14px; color: var(--text-muted);
  padding: 4px 0; transition: color .3s;
  display: flex; align-items: center; gap: 8px;
}
.toc-link::before {
  content: "";
  width: 4px; height: 4px;
  border-radius: 50%;
  background: var(--line);
  flex: none;
  transition: background .3s;
}
.toc-link:hover { color: var(--teal); }
.toc-link:hover::before { background: var(--teal); }

/* ===== 价格卡片 ===== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  margin: 32px 0;
}
.pricing-card {
  background: var(--card-bg);
  border: 1px solid var(--line-soft);
  border-radius: 8px;
  padding: 36px 28px;
  text-align: center;
  transition: all .5s var(--ease-soft);
  position: relative;
  overflow: hidden;
}
.pricing-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 40px -12px rgba(0,0,0,.1);
}
.dark-mode .pricing-card:hover {
  box-shadow: 0 20px 40px -12px rgba(0,0,0,.3);
}
.pricing-card.featured {
  border-color: var(--teal);
  box-shadow: 0 0 0 1px var(--teal) inset;
}
.pricing-card.featured::before {
  content: "推荐";
  position: absolute;
  top: 14px;
  right: -28px;
  background: var(--teal-deep);
  color: #f2fbfa;
  font-size: 10px;
  font-weight: 600;
  padding: 3px 32px;
  transform: rotate(45deg);
  letter-spacing: .06em;
}
.dark-mode .pricing-card.featured::before {
  background: var(--teal);
  color: var(--night-0);
}
.pricing-name {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 20px;
  color: var(--text);
  margin-bottom: 8px;
}
.pricing-price {
  font-family: var(--serif);
  font-weight: 900;
  font-size: 36px;
  color: var(--teal-deep);
  margin-bottom: 6px;
}
.dark-mode .pricing-price {
  color: var(--teal-bright);
}
.pricing-price .unit {
  font-size: 14px;
  font-weight: 400;
  color: var(--text-muted);
}
.pricing-desc {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 20px;
}
.pricing-features {
  text-align: left;
  padding: 0;
  margin-bottom: 24px;
}
.pricing-features li {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-muted);
  padding: 6px 0;
}
.pricing-features li::before {
  content: "✓";
  color: var(--teal);
  font-weight: 700;
  font-size: 14px;
  flex: none;
}
@media (max-width: 640px) {
  .pricing-grid { grid-template-columns: 1fr; }
  .pricing-card { padding: 28px 20px; }
}

/* ===== 页脚 ===== */
.site-foot {
  margin-left: var(--sidebar-w);
  border-top: 1px solid var(--line-soft);
  padding: 32px 64px;
}
.foot-inner {
  max-width: 1360px;
  margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.foot-brand { display: flex; align-items: center; gap: 12px; }
.foot-brand img { width: 36px; height: 36px; border-radius: 6px; }
.foot-brand b { display: block; font-family: var(--serif); font-size: 13px; color: var(--text); }
.foot-brand p { font-size: 11px; color: var(--text-faint); margin: 0; }
.foot-nav { display: flex; gap: 20px; }
.foot-nav a { font-size: 12px; color: var(--text-muted); transition: color .3s; }
.foot-nav a:hover { color: var(--teal); }
.foot-copy { font-size: 11px; color: var(--text-faint); flex: none; }
.back-top {
  position: fixed; bottom: 32px; right: 32px;
  width: 42px; height: 42px;
  border-radius: 50%;
  background: var(--card-bg);
  border: 1px solid var(--line);
  color: var(--text-muted);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  opacity: 0; transform: translateY(16px);
  transition: all .5s var(--ease-soft);
  z-index: 30;
  box-shadow: 0 4px 16px rgba(0,0,0,.06);
}
.back-top.visible { opacity: 1; transform: translateY(0); }
.back-top:hover { color: var(--teal); border-color: var(--teal); transform: translateY(-2px); }
.back-top svg { width: 18px; height: 18px; }
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 1s var(--ease-long), transform 1s var(--ease-long); transition-delay: var(--d, 0s); }
.reveal.in-view { opacity: 1; transform: translateY(0); }
.mobile-menu-btn { display: none; background: none; border: none; color: var(--text-muted); cursor: pointer; padding: 4px; }
.mobile-menu-btn svg { width: 22px; height: 22px; }
.sidebar-overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,.3); z-index: 45; backdrop-filter: blur(4px); }
.sidebar-overlay.open { display: block; }

/* ===== 顶部赞助条 ===== */
.top-bar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 44px;
  z-index: 65;
  background: linear-gradient(135deg, #0d9488, #0f766e);
  border-bottom: 1px solid rgba(255,255,255,.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  letter-spacing: .04em;
  box-shadow: 0 2px 12px rgba(13, 148, 136, .35);
  transition: background .5s var(--ease-soft);
}
.dark-mode .top-bar {
  background: linear-gradient(135deg, #087a76, #065f5a);
  box-shadow: 0 2px 12px rgba(8, 122, 118, .35);
}
.top-bar a {
  color: #fff !important;
  border-bottom: 1.5px solid rgba(255,255,255,.5);
  padding-bottom: 1px;
  transition: border-color .3s;
}
.top-bar a:hover {
  border-bottom-color: #fff;
  text-decoration: none !important;
}
.top-bar .sparkle {
  display: inline-block;
  animation: sparkle 1.8s ease-in-out infinite;
}
@keyframes sparkle {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: .6; transform: scale(1.2); }
}
.site-head { top: 44px; }
.sidebar { top: calc(72px + 44px); }
.layout { padding-top: calc(72px + 44px); }
.scroll-progress { top: 44px; }
@media (max-width: 1024px) {
  .sidebar.mobile-open { top: calc(72px + 44px); }
}
@media (max-width: 1024px) {
  .sidebar { display: none; }
  .main-content { margin-left: 0; max-width: 100%; padding: 40px 32px 80px; }
  .site-foot { margin-left: 0; padding: 24px 32px; }
  .head-nav { display: none; }
  .mobile-menu-btn { display: flex; align-items: center; }
  .sidebar.mobile-open {
    display: block; position: fixed; top: 72px; left: 0; bottom: 0; width: 280px;
    z-index: 50; box-shadow: 4px 0 30px rgba(0,0,0,.1); border-right: none;
  }
}
@media (max-width: 640px) {
  .head-inner { padding: 0 20px; gap: 16px; }
  .main-content { padding: 28px 20px 60px; }
  .site-foot { padding: 20px; }
  .card { padding: 20px; }
  .foot-inner { flex-direction: column; text-align: center; }
}