/* ==========================================================================
   抖音流量推广 - 全站样式
   纯静态、零依赖、移动优先
   ========================================================================== */

:root {
  --bg: #08080d;
  --bg-soft: #0d0d16;
  --surface: rgba(255, 255, 255, 0.045);
  --surface-2: rgba(255, 255, 255, 0.075);
  --border: rgba(255, 255, 255, 0.09);
  --border-strong: rgba(255, 255, 255, 0.16);
  --text: #f2f3f8;
  --text-dim: #b6bbcc;
  --muted: #8a90a6;
  --cyan: #25f4ee;
  --pink: #fe2c55;
  --violet: #8b5cf6;
  --grad: linear-gradient(118deg, #25f4ee 0%, #7c5cff 48%, #fe2c55 100%);
  --grad-soft: linear-gradient(118deg, rgba(37, 244, 238, .16), rgba(254, 44, 85, .16));
  --radius: 18px;
  --radius-sm: 12px;
  --max: 1180px;
  --shadow: 0 24px 70px rgba(0, 0, 0, .5);
  --header-h: 68px;
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 16px;
  line-height: 1.8;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* 全站背景光晕 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(680px 420px at 12% -6%, rgba(37, 244, 238, .13), transparent 62%),
    radial-gradient(720px 460px at 88% 4%, rgba(254, 44, 85, .13), transparent 62%),
    radial-gradient(900px 620px at 50% 108%, rgba(124, 92, 255, .10), transparent 68%);
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
button { font: inherit; cursor: pointer; }
strong { color: #fff; font-weight: 700; }

/* ===================== 布局 ===================== */
.wrap { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 20px; }

.section { padding: 76px 0; position: relative; }
.section--tight { padding: 54px 0; }

.section-head { max-width: 760px; margin: 0 auto 46px; text-align: center; }
.section-head--left { margin-left: 0; text-align: left; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; letter-spacing: .12em; text-transform: uppercase;
  color: var(--cyan); font-weight: 700; margin-bottom: 14px;
}
.eyebrow::before {
  content: ""; width: 22px; height: 2px; border-radius: 2px; background: var(--grad);
}

h1, h2, h3, h4 { line-height: 1.32; font-weight: 800; letter-spacing: -.01em; }

.h1 { font-size: clamp(30px, 5.4vw, 52px); }
.h2 { font-size: clamp(24px, 3.4vw, 36px); margin-bottom: 16px; }
.h3 { font-size: clamp(18px, 2.2vw, 21px); font-weight: 700; margin-bottom: 10px; }

.lead { color: var(--text-dim); font-size: clamp(15px, 1.6vw, 17px); }
.muted { color: var(--muted); }

.grad-text {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ===================== 按钮 ===================== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  padding: 13px 26px; border-radius: 999px;
  font-size: 15px; font-weight: 700;
  border: 1px solid transparent; white-space: nowrap;
  transition: transform .22s ease, box-shadow .22s ease, background .22s ease, border-color .22s ease;
}
.btn:active { transform: scale(.97); }

.btn-primary {
  background: var(--grad);
  color: #08080d;
  box-shadow: 0 10px 34px rgba(254, 44, 85, .32);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 44px rgba(254, 44, 85, .46); }

.btn-ghost {
  background: var(--surface);
  border-color: var(--border-strong);
  color: var(--text);
}
.btn-ghost:hover { background: var(--surface-2); border-color: rgba(37, 244, 238, .5); }

.btn-lg { padding: 17px 38px; font-size: 17px; }
.btn-block { width: 100%; }

.btn-arrow { transition: transform .22s ease; }
.btn:hover .btn-arrow { transform: translateX(4px); }

/* ===================== 顶部导航 ===================== */
.header {
  position: sticky; top: 0; z-index: 90;
  height: var(--header-h);
  display: flex; align-items: center;
  background: rgba(8, 8, 13, .72);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border);
}
.header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 18px; }

.logo { display: flex; align-items: center; gap: 11px; font-weight: 800; font-size: 17px; letter-spacing: -.01em; }
.logo-mark {
  width: 36px; height: 36px; border-radius: 11px; flex: none;
  background: var(--grad);
  display: grid; place-items: center;
  color: #08080d; font-weight: 900; font-size: 17px;
  box-shadow: 0 6px 20px rgba(254, 44, 85, .34);
}
.logo small { display: block; font-size: 11px; font-weight: 500; color: var(--muted); letter-spacing: .04em; line-height: 1.2; }

.nav { display: flex; align-items: center; gap: 4px; }
.nav a {
  padding: 8px 14px; border-radius: 10px;
  font-size: 14.5px; color: var(--text-dim);
  transition: color .2s, background .2s;
}
.nav a:hover { color: #fff; background: var(--surface); }
.nav a[aria-current="page"] { color: #fff; background: var(--surface-2); }

.header-cta { display: flex; align-items: center; gap: 10px; }
.header-cta .btn { padding: 10px 20px; font-size: 14px; }

.nav-toggle {
  display: none; width: 42px; height: 42px; border-radius: 11px;
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text); place-items: center; flex: none;
}
.nav-toggle span { display: block; width: 18px; height: 2px; background: currentColor; border-radius: 2px; position: relative; }
.nav-toggle span::before, .nav-toggle span::after {
  content: ""; position: absolute; left: 0; width: 18px; height: 2px; background: currentColor; border-radius: 2px;
}
.nav-toggle span::before { top: -6px; }
.nav-toggle span::after { top: 6px; }

/* ===================== Hero ===================== */
.hero { padding: 66px 0 58px; position: relative; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1.08fr .92fr; gap: 52px; align-items: center; }

.badge {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 7px 16px; border-radius: 999px;
  background: var(--surface); border: 1px solid var(--border-strong);
  font-size: 13px; color: var(--text-dim); margin-bottom: 22px;
}
.dot {
  width: 8px; height: 8px; border-radius: 50%; background: #4ade80; flex: none;
  box-shadow: 0 0 0 0 rgba(74, 222, 128, .7);
  animation: pulse 2.2s infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(74, 222, 128, .65); }
  70% { box-shadow: 0 0 0 9px rgba(74, 222, 128, 0); }
  100% { box-shadow: 0 0 0 0 rgba(74, 222, 128, 0); }
}

.hero p.lead { margin: 18px 0 30px; max-width: 620px; }

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 34px; }

.hero-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; max-width: 560px; }
.stat {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 16px 18px;
}
.stat b { display: block; font-size: clamp(19px, 2.4vw, 25px); font-weight: 800; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat span { font-size: 12.5px; color: var(--muted); }

/* Hero 右侧视觉卡片 */
.hero-visual { position: relative; }
.hero-card {
  position: relative; border-radius: 24px; padding: 26px;
  background: linear-gradient(160deg, rgba(255, 255, 255, .1), rgba(255, 255, 255, .02));
  border: 1px solid var(--border-strong);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}
.hero-card h3 { font-size: 16px; margin-bottom: 18px; display: flex; align-items: center; gap: 9px; }
.hero-card h3 i { width: 4px; height: 17px; border-radius: 3px; background: var(--grad); flex: none; }
.bar-row { margin-bottom: 16px; }
.bar-row:last-child { margin-bottom: 0; }
.bar-label { display: flex; justify-content: space-between; font-size: 13px; color: var(--text-dim); margin-bottom: 7px; }
.bar-track { height: 8px; border-radius: 6px; background: rgba(255, 255, 255, .08); overflow: hidden; }
.bar-fill { height: 100%; border-radius: 6px; background: var(--grad); width: 0; transition: width 1.3s cubic-bezier(.22, 1, .36, 1); }
.reveal.in .bar-fill { width: var(--w, 70%); }

.hero-float {
  position: absolute; right: -8px; bottom: -18px;
  background: rgba(13, 13, 22, .92); border: 1px solid var(--border-strong);
  border-radius: 14px; padding: 12px 16px; font-size: 12.5px;
  box-shadow: var(--shadow);
  animation: floaty 4.2s ease-in-out infinite;
}
.hero-float b { color: var(--cyan); }
@keyframes floaty { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-9px); } }

/* ===================== 通用卡片网格 ===================== */
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  transition: transform .26s ease, border-color .26s ease, background .26s ease, box-shadow .26s ease;
}
.card:hover {
  transform: translateY(-4px);
  border-color: rgba(37, 244, 238, .35);
  background: var(--surface-2);
  box-shadow: 0 18px 46px rgba(0, 0, 0, .38);
}
.card h3 { font-size: 17.5px; font-weight: 700; margin-bottom: 9px; }
.card p { color: var(--text-dim); font-size: 14.5px; line-height: 1.78; }

.icon-badge {
  width: 46px; height: 46px; border-radius: 13px; margin-bottom: 16px;
  display: grid; place-items: center; font-size: 21px;
  background: var(--grad-soft); border: 1px solid var(--border-strong);
}

/* 文字型内容块（利于爬虫理解） */
.prose { max-width: 860px; }
.prose h2 { font-size: clamp(21px, 2.6vw, 27px); margin: 0 0 14px; }
.prose h3 { font-size: 18px; margin: 28px 0 10px; }
.prose p { color: var(--text-dim); margin-bottom: 16px; }
.prose ul { margin: 0 0 18px; }
.prose ul li {
  position: relative; padding-left: 24px; margin-bottom: 10px; color: var(--text-dim);
}
.prose ul li::before {
  content: ""; position: absolute; left: 4px; top: .72em;
  width: 7px; height: 7px; border-radius: 50%; background: var(--grad);
}

/* ===================== 流程步骤 ===================== */
.steps { counter-reset: step; display: grid; gap: 18px; grid-template-columns: repeat(4, 1fr); }
.step {
  position: relative; padding: 26px 24px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.step::before {
  counter-increment: step; content: "0" counter(step);
  font-size: 30px; font-weight: 900; line-height: 1; display: block; margin-bottom: 14px;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
}
.step h3 { font-size: 16.5px; font-weight: 700; margin-bottom: 8px; }
.step p { font-size: 14px; color: var(--text-dim); }

/* ===================== 中部跳转 CTA 区 ===================== */
.cta-band {
  position: relative; overflow: hidden;
  border-radius: 26px; padding: 52px 40px; text-align: center;
  background: linear-gradient(130deg, rgba(37, 244, 238, .12), rgba(124, 92, 255, .14) 48%, rgba(254, 44, 85, .14));
  border: 1px solid var(--border-strong);
  box-shadow: var(--shadow);
}
.cta-band::after {
  content: ""; position: absolute; inset: -40% -10% auto auto; width: 420px; height: 420px;
  background: radial-gradient(circle, rgba(254, 44, 85, .22), transparent 68%);
  pointer-events: none;
}
.cta-band h2 { font-size: clamp(23px, 3.2vw, 34px); margin-bottom: 14px; }
.cta-band p { color: var(--text-dim); max-width: 620px; margin: 0 auto 28px; }
.cta-actions { display: flex; justify-content: center; flex-wrap: wrap; gap: 14px; }
.cta-note { margin-top: 18px; font-size: 13px; color: var(--muted); }

/* ===================== 问答 ===================== */
.faq { max-width: 860px; margin: 0 auto; }
.faq-item {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-sm); margin-bottom: 12px; overflow: hidden;
  transition: border-color .24s ease, background .24s ease;
}
.faq-item:hover { border-color: var(--border-strong); }
.faq-item.open { border-color: rgba(37, 244, 238, .4); background: var(--surface-2); }
.faq-q {
  width: 100%; text-align: left; background: none; border: 0; color: var(--text);
  padding: 19px 54px 19px 22px; font-size: 16px; font-weight: 700;
  position: relative; line-height: 1.6;
}
.faq-q::after {
  content: "+"; position: absolute; right: 22px; top: 50%; transform: translateY(-50%);
  font-size: 22px; font-weight: 400; color: var(--cyan); transition: transform .26s ease;
}
.faq-item.open .faq-q::after { transform: translateY(-50%) rotate(45deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .34s ease; }
.faq-a-inner { padding: 0 22px 20px; color: var(--text-dim); font-size: 14.6px; }

/* ===================== 数据表 ===================== */
.table-wrap { overflow-x: auto; border-radius: var(--radius); border: 1px solid var(--border); }
table { width: 100%; border-collapse: collapse; min-width: 560px; font-size: 14.5px; }
thead th {
  background: var(--surface-2); text-align: left; padding: 15px 20px;
  font-size: 13.5px; letter-spacing: .03em; color: var(--text);
  border-bottom: 1px solid var(--border); white-space: nowrap;
}
tbody td { padding: 14px 20px; color: var(--text-dim); border-bottom: 1px solid var(--border); }
tbody tr:last-child td { border-bottom: 0; }
tbody tr:hover td { background: var(--surface); }

/* ===================== 面包屑 ===================== */
.crumb { padding: 20px 0 0; font-size: 13.5px; color: var(--muted); }
.crumb a { color: var(--text-dim); }
.crumb a:hover { color: var(--cyan); }
.crumb span { margin: 0 8px; opacity: .5; }

/* ===================== 页脚 ===================== */
.footer {
  margin-top: 30px; border-top: 1px solid var(--border);
  background: var(--bg-soft); padding: 54px 0 28px;
}
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1.2fr; gap: 34px; }
.footer h4 { font-size: 14.5px; margin-bottom: 16px; color: #fff; }
.footer p { color: var(--muted); font-size: 13.6px; }
.footer li { margin-bottom: 10px; }
.footer li a { color: var(--text-dim); font-size: 13.8px; transition: color .2s; }
.footer li a:hover { color: var(--cyan); }
.footer .logo { margin-bottom: 14px; }
.footer-bottom {
  margin-top: 40px; padding-top: 22px; border-top: 1px solid var(--border);
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px;
  font-size: 13px; color: var(--muted);
}

/* ===================== 悬浮跳转按钮 ===================== */
.float-cta {
  position: fixed; z-index: 95;
  right: 20px; bottom: 20px;
  display: inline-flex; align-items: center; gap: 9px;
  padding: 15px 26px; border-radius: 999px;
  background: var(--grad); color: #08080d;
  font-weight: 800; font-size: 15px;
  box-shadow: 0 14px 40px rgba(254, 44, 85, .45);
  transition: transform .24s ease, box-shadow .24s ease;
}
.float-cta:hover { transform: translateY(-3px) scale(1.02); box-shadow: 0 20px 52px rgba(254, 44, 85, .58); }
.float-cta .dot { background: #08080d; animation: none; box-shadow: none; }

/* ===================== 滚动进场 ===================== */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .hero-float, .dot { animation: none; }
  html { scroll-behavior: auto; }
}

/* ===================== 响应式 ===================== */
@media (max-width: 1020px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .hero-visual { max-width: 520px; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 860px) {
  .nav-toggle { display: grid; }
  .nav {
    position: fixed; inset: var(--header-h) 0 auto 0;
    flex-direction: column; align-items: stretch; gap: 2px;
    background: rgba(10, 10, 16, .98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    padding: 14px 20px 22px;
    transform: translateY(-130%); opacity: 0; pointer-events: none;
    transition: transform .3s ease, opacity .3s ease;
  }
  .nav.open { transform: none; opacity: 1; pointer-events: auto; }
  .nav a { padding: 13px 14px; font-size: 15.5px; border-radius: 12px; }
  .header-cta .btn:not(.nav-toggle) { display: none; }
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .section { padding: 58px 0; }
}

@media (max-width: 560px) {
  body { font-size: 15.5px; }
  .hero-stats { grid-template-columns: 1fr; }
  .grid-4, .steps { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 26px; }
  .cta-band { padding: 40px 22px; border-radius: 20px; }
  .card { padding: 22px; }
  .float-cta { right: 14px; left: 14px; bottom: 14px; justify-content: center; }
  .footer { padding-bottom: 92px; }
}