/* ==========================================================================
   抖音怎么推广 - 全站样式
   深靛紫底 + 亮紫/桃橙（区别于站1黑底青粉、站2浅蓝紫、站3墨绿、站4米白、站5酒红、站6藏青）
   纯静态、零依赖、移动优先
   ========================================================================== */

:root {
  --bg: #0e0819;
  --bg-soft: #160d29;
  --bg-deep: #0a0513;
  --panel: rgba(255, 255, 255, 0.05);
  --panel-2: rgba(255, 255, 255, 0.085);
  --edge: rgba(170, 130, 255, 0.22);
  --edge-strong: rgba(170, 130, 255, 0.45);
  --ink: #f3eefc;
  --ink-dim: #c4b6e0;
  --ink-mute: #8d7fae;
  --purple: #9d6bff;
  --purple-bright: #7b5cff;
  --peach: #ff9e64;
  --grad: linear-gradient(120deg, #7b5cff 0%, #9d6bff 52%, #ff9e64 100%);
  --grad-soft: linear-gradient(120deg, rgba(123, 92, 255, .18), rgba(255, 158, 100, .14));
  --radius: 18px;
  --radius-sm: 12px;
  --max: 1120px;
  --shadow: 0 22px 60px rgba(0, 0, 0, .55);
  --header-h: 66px;
}

*, *::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(--ink);
  font-size: 16px;
  line-height: 1.85;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

.shell { max-width: var(--max); margin: 0 auto; padding: 0 22px; }

a { color: var(--purple); text-decoration: none; }
a:hover { color: var(--peach); }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  height: var(--header-h);
  background: rgba(14, 8, 25, 0.82);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--edge);
  transition: box-shadow .25s;
}
.topbar.scrolled { box-shadow: 0 10px 30px rgba(0, 0, 0, .45); }
.topbar-inner { display: flex; align-items: center; justify-content: space-between; height: 100%; }

.logo { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); font-weight: 700; }
.logo-mark {
  width: 14px; height: 14px; border-radius: 4px;
  background: var(--grad);
  box-shadow: 0 0 14px rgba(157, 107, 255, .6);
}
.logo-name { font-size: 17px; letter-spacing: .5px; }

.menu { display: flex; gap: 26px; }
.menu a { color: var(--ink-dim); font-size: 14.5px; transition: color .2s; }
.menu a:hover { color: var(--ink); }

@media (max-width: 640px) {
  .menu { gap: 14px; }
  .menu a { font-size: 13px; }
}

/* ---------- 顶部渐变横幅 ---------- */
.banner {
  position: relative;
  padding: 88px 0 72px;
  background:
    radial-gradient(900px 420px at 15% -10%, rgba(123, 92, 255, .28), transparent 60%),
    radial-gradient(700px 380px at 90% 0%, rgba(255, 158, 100, .16), transparent 55%),
    var(--bg-deep);
  border-bottom: 1px solid var(--edge);
  overflow: hidden;
}
.banner::after {
  content: ""; position: absolute; inset: auto 0 -1px 0; height: 120px;
  background: linear-gradient(to bottom, transparent, var(--bg));
  pointer-events: none;
}
.banner-sub { padding: 64px 0 56px; }

.banner-kicker {
  display: inline-block;
  font-size: 13px; letter-spacing: 3px;
  color: var(--peach);
  border: 1px solid var(--edge-strong);
  border-radius: 999px;
  padding: 4px 16px;
  margin-bottom: 20px;
  background: var(--panel);
}

.banner h1 {
  font-size: clamp(34px, 6vw, 52px);
  line-height: 1.25;
  font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 18px;
}

.banner-sub-p, .banner-sub { max-width: 720px; }
.banner-sub { color: var(--ink-dim); font-size: 16.5px; }

.banner-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 30px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 13px 30px;
  border-radius: 999px;
  font-size: 15.5px; font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .2s, box-shadow .2s, background .2s, color .2s;
}
.btn-main {
  background: var(--grad);
  color: #fff;
  box-shadow: 0 10px 30px rgba(123, 92, 255, .4);
}
.btn-main:hover { transform: translateY(-2px); color: #fff; box-shadow: 0 14px 38px rgba(123, 92, 255, .55); }
.btn-ghost {
  background: var(--panel);
  border-color: var(--edge-strong);
  color: var(--ink);
}
.btn-ghost:hover { background: var(--panel-2); color: var(--ink); }
.btn-light {
  background: #fff; color: #3a2450;
  box-shadow: 0 12px 34px rgba(0, 0, 0, .35);
}
.btn-light:hover { transform: translateY(-2px); color: #2a1840; }

.banner-stats {
  display: flex; flex-wrap: wrap; gap: 40px;
  list-style: none; margin-top: 44px;
}
.banner-stats b {
  display: block;
  font-size: 30px; font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.banner-stats span { font-size: 13.5px; color: var(--ink-mute); }

/* ---------- 区块 ---------- */
.sec { padding: 72px 0; }
.sec-alt { background: var(--bg-soft); border-top: 1px solid var(--edge); border-bottom: 1px solid var(--edge); }

.sec-title {
  font-size: clamp(24px, 4vw, 32px);
  font-weight: 800;
  margin-bottom: 12px;
  text-align: center;
}
.sec-lead { text-align: center; color: var(--ink-dim); max-width: 640px; margin: 0 auto 44px; }

/* ---------- 方法卡片 ---------- */
.method-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}
.method-card {
  background: var(--panel);
  border: 1px solid var(--edge);
  border-radius: var(--radius);
  padding: 28px 24px;
  transition: transform .25s, border-color .25s;
}
.method-card:hover { transform: translateY(-4px); border-color: var(--edge-strong); }
.method-card h3 { font-size: 18px; margin: 14px 0 10px; }
.method-card p { font-size: 14.5px; color: var(--ink-dim); }

.m-icon {
  width: 46px; height: 46px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 13px;
  font-weight: 800; font-size: 15px;
  color: #fff;
  letter-spacing: 1px;
}
.m-1 { background: linear-gradient(135deg, #7b5cff, #9d6bff); }
.m-2 { background: linear-gradient(135deg, #9d6bff, #ff9e64); }
.m-3 { background: linear-gradient(135deg, #ff9e64, #ff7e67); }
.m-4 { background: linear-gradient(135deg, #6b8bff, #7b5cff); }

/* ---------- 时间线 ---------- */
.timeline { list-style: none; max-width: 760px; margin: 0 auto; }
.timeline li {
  position: relative;
  display: flex; gap: 24px;
  padding: 0 0 40px 0;
}
.timeline li::before {
  content: ""; position: absolute; top: 46px; bottom: 4px; left: 21px;
  width: 2px;
  background: linear-gradient(to bottom, var(--edge-strong), transparent);
}
.timeline li:last-child::before { display: none; }

.t-node {
  flex: none;
  width: 44px; height: 44px;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 17px;
  color: #fff;
  background: var(--grad);
  box-shadow: 0 0 0 5px rgba(157, 107, 255, .14);
}
.t-body h3 { font-size: 18.5px; margin-bottom: 8px; }
.t-body p { font-size: 15px; color: var(--ink-dim); }

/* ---------- 教程引导盒 ---------- */
.guide-box {
  display: flex; align-items: center; justify-content: space-between;
  gap: 28px; flex-wrap: wrap;
  background: var(--grad-soft);
  border: 1px solid var(--edge-strong);
  border-radius: var(--radius);
  padding: 38px 34px;
}
.guide-text h2 { font-size: 24px; margin-bottom: 10px; }
.guide-text p { color: var(--ink-dim); max-width: 560px; font-size: 15px; }

/* ---------- 教程页清单 ---------- */
.lesson { max-width: 780px; margin: 0 auto; }
.lesson > p { color: var(--ink-dim); margin-bottom: 22px; font-size: 16px; }
.check-list { list-style: none; display: grid; gap: 12px; }
.check-list li {
  position: relative;
  padding: 14px 18px 14px 46px;
  background: var(--panel);
  border: 1px solid var(--edge);
  border-radius: var(--radius-sm);
  font-size: 15px;
}
.check-list li::before {
  content: "✓"; position: absolute; left: 16px; top: 50%;
  transform: translateY(-50%);
  width: 22px; height: 22px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 6px;
  background: var(--grad);
  color: #fff; font-size: 13px; font-weight: 800;
}

/* ---------- 答疑 ---------- */
.ask-list { max-width: 780px; margin: 0 auto; display: grid; gap: 14px; }
.ask-list details {
  background: var(--panel);
  border: 1px solid var(--edge);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  transition: border-color .2s;
}
.ask-list details[open] { border-color: var(--edge-strong); }
.ask-list summary {
  cursor: pointer; font-weight: 700; font-size: 16px;
  list-style: none;
}
.ask-list summary::-webkit-details-marker { display: none; }
.ask-list summary::after {
  content: "+"; float: right; color: var(--peach); font-size: 20px; font-weight: 700;
}
.ask-list details[open] summary::after { content: "−"; }
.ask-list details p { margin-top: 12px; color: var(--ink-dim); font-size: 14.5px; }

/* ---------- 底部 CTA ---------- */
.cta-band {
  padding: 76px 0;
  text-align: center;
  background:
    radial-gradient(700px 300px at 50% 100%, rgba(157, 107, 255, .22), transparent 65%),
    var(--bg-deep);
  border-top: 1px solid var(--edge);
}
.cta-band h2 { font-size: clamp(24px, 4vw, 32px); font-weight: 800; margin-bottom: 12px; }
.cta-band p { color: var(--ink-dim); margin-bottom: 30px; }

/* ---------- 页脚 ---------- */
.foot {
  border-top: 1px solid var(--edge);
  padding: 34px 0;
  background: var(--bg-deep);
}
.foot-inner { text-align: center; display: grid; gap: 10px; }
.foot-menu { display: flex; justify-content: center; gap: 22px; }
.foot-menu a { color: var(--ink-mute); font-size: 14px; }
.foot-menu a:hover { color: var(--ink); }
.foot-note { color: var(--ink-mute); font-size: 12.5px; }

/* ---------- 入场动画 ---------- */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s, transform .6s; }
.reveal.in { opacity: 1; transform: none; }

/* ---------- 404 页 ---------- */
.body-404 { display: flex; align-items: center; justify-content: center; min-height: 100vh; text-align: center; }
.box-404 h1 {
  font-size: 88px; font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}
.box-404 p { color: var(--ink-dim); margin: 14px 0 28px; }