/* ==========================================================================
   抖音短视频推广 - 全站样式
   暖米白底 + 橙红/暖金（区别于站1深色青粉、站2冷浅蓝紫、站3深墨绿）
   纯静态、零依赖、移动优先
   ========================================================================== */

:root {
  --bg: #fbf6ee;
  --bg-alt: #f5eddd;
  --card: #ffffff;
  --card-soft: #fdfaf4;
  --line: #eadfc8;
  --line-strong: #dccda9;
  --ink: #2c2013;
  --ink-dim: #6b5a44;
  --ink-mute: #a08a6c;
  --orange: #e8481f;
  --orange-deep: #c23413;
  --gold: #e89b1c;
  --grad: linear-gradient(120deg, #e8481f 0%, #e8741c 55%, #e89b1c 100%);
  --radius: 16px;
  --radius-sm: 10px;
  --max: 1140px;
  --shadow: 0 16px 44px rgba(120, 70, 20, .12);
  --shadow-sm: 0 6px 20px rgba(120, 70, 20, .09);
}

*, *::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;
  -webkit-font-smoothing: antialiased;
}

/* 顶部暖色光带 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(640px 380px at 8% -6%, rgba(232, 72, 31, .10), transparent 60%),
    radial-gradient(700px 420px at 94% 0%, rgba(232, 155, 28, .12), transparent 62%);
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
details summary { cursor: pointer; list-style: none; }
details summary::-webkit-details-marker { display: none; }

.shell { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 22px; }

/* ===================== 顶栏 ===================== */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(251, 246, 238, .88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
  transition: box-shadow .3s;
}
.topbar.scrolled { box-shadow: var(--shadow-sm); }

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; font-size: 17px; }
.logo-dot {
  width: 14px; height: 14px; border-radius: 4px;
  background: var(--grad);
  box-shadow: 0 3px 10px rgba(232, 72, 31, .45);
}

.menu { display: flex; gap: 26px; font-size: 14.5px; color: var(--ink-dim); }
.menu a { position: relative; padding: 6px 0; transition: color .25s; }
.menu a:hover { color: var(--orange); }
.menu a::after {
  content: ""; position: absolute; left: 0; bottom: 0;
  width: 0; height: 2px; border-radius: 2px; background: var(--grad);
  transition: width .25s;
}
.menu a:hover::after { width: 100%; }

/* ===================== 首屏 ===================== */
.hero { padding: 72px 0 84px; overflow: hidden; }

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr .85fr;
  gap: 56px;
  align-items: center;
}

.hero-badge {
  display: inline-block;
  padding: 7px 16px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  background: var(--card);
  font-size: 13px;
  font-weight: 700;
  color: var(--orange-deep);
  letter-spacing: .04em;
  margin-bottom: 20px;
}

.hero h1 {
  font-size: clamp(30px, 4.6vw, 48px);
  line-height: 1.28;
  font-weight: 900;
  letter-spacing: .01em;
}
.hero h1 em {
  font-style: normal;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lead {
  margin-top: 20px;
  max-width: 520px;
  color: var(--ink-dim);
  font-size: 16.5px;
}

.hero-btns { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 30px; }

.cta {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 13px 30px;
  border-radius: 999px;
  font-size: 16px;
  font-weight: 800;
  transition: transform .22s, box-shadow .22s;
}
.cta-main {
  color: #fff;
  background: var(--grad);
  box-shadow: 0 10px 28px rgba(232, 72, 31, .38);
}
.cta-main:hover { transform: translateY(-3px); box-shadow: 0 16px 36px rgba(232, 72, 31, .46); }
.cta-line {
  color: var(--orange-deep);
  border: 2px solid var(--line-strong);
  background: var(--card);
}
.cta-line:hover { transform: translateY(-3px); border-color: var(--orange); }

.hero-marks { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
.hero-marks li {
  font-size: 13px; font-weight: 700; color: var(--ink-dim);
  padding: 6px 14px;
  border-radius: 999px;
  background: var(--bg-alt);
  border: 1px dashed var(--line-strong);
}

/* 首屏右侧数据卡 */
.hero-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 26px 26px 22px;
  position: relative;
  overflow: hidden;
}
.hero-card::before {
  content: "";
  position: absolute; top: 0; left: 0; right: 0; height: 4px;
  background: var(--grad);
}
.hc-title { font-size: 14px; font-weight: 800; color: var(--ink-dim); letter-spacing: .08em; }
.hc-list { margin-top: 16px; display: grid; gap: 12px; }
.hc-list li {
  display: flex; justify-content: space-between; align-items: center;
  padding: 12px 16px;
  background: var(--card-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-size: 14.5px;
  color: var(--ink-dim);
}
.hc-list b { color: var(--orange); font-size: 17px; font-weight: 900; }

.hc-bar {
  margin-top: 18px;
  height: 8px;
  border-radius: 999px;
  background: var(--bg-alt);
  overflow: hidden;
}
.hc-bar i {
  display: block; height: 100%; width: 0;
  border-radius: 999px;
  background: var(--grad);
  animation: grow 2.4s ease .4s forwards;
}
@keyframes grow { to { width: 82%; } }

.hc-note { margin-top: 10px; font-size: 12.5px; color: var(--ink-mute); text-align: right; }

/* ===================== 通用区块 ===================== */
.block { padding: 72px 0; }
.block-alt { background: var(--bg-alt); }

.block-head { max-width: 680px; margin-bottom: 42px; }
.block-head h2 { font-size: clamp(24px, 3vw, 32px); font-weight: 900; }
.block-head p { margin-top: 10px; color: var(--ink-dim); }

/* ===================== 推广项目 ===================== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.p-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px;
  transition: transform .25s, box-shadow .25s, border-color .25s;
}
.p-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow);
  border-color: var(--line-strong);
}

.p-ico {
  display: inline-flex; align-items: center; justify-content: center;
  width: 46px; height: 46px;
  border-radius: 13px;
  color: #fff;
  font-size: 19px;
  font-weight: 900;
  margin-bottom: 16px;
}
.ico-play { background: linear-gradient(135deg, #e8481f, #f06a30); }
.ico-like { background: linear-gradient(135deg, #e8741c, #f2924a); }
.ico-cmt { background: linear-gradient(135deg, #e89b1c, #f2b356); }
.ico-fans { background: linear-gradient(135deg, #d95c1a, #e8772f); }
.ico-live { background: linear-gradient(135deg, #c23413, #dd5224); }
.ico-hot { background: linear-gradient(135deg, #e8481f, #e89b1c); }

.p-card h3 { font-size: 18px; font-weight: 800; }
.p-card p { margin-top: 8px; font-size: 14.5px; color: var(--ink-dim); }

/* ===================== 适用场景 ===================== */
.scene-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.scene-item {
  position: relative;
  background: var(--card);
  border-radius: var(--radius);
  border-left: 4px solid var(--orange);
  padding: 22px 24px;
  box-shadow: var(--shadow-sm);
}
.scene-item:nth-child(even) { border-left-color: var(--gold); }
.scene-item b { font-size: 17px; font-weight: 800; }
.scene-item p { margin-top: 6px; font-size: 14.5px; color: var(--ink-dim); }

/* ===================== 步骤 ===================== */
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  counter-reset: step;
}
.steps li {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px 20px;
  transition: transform .25s, box-shadow .25s;
}
.steps li:hover { transform: translateY(-4px); box-shadow: var(--shadow); }

.step-no {
  display: block;
  font-size: 26px;
  font-weight: 900;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 8px;
}
.steps h3 { font-size: 16.5px; font-weight: 800; }
.steps p { margin-top: 6px; font-size: 14px; color: var(--ink-dim); }

/* ===================== 答疑 ===================== */
.ask-list { display: grid; gap: 12px; max-width: 820px; }

.ask-list details {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 16px 22px;
  transition: border-color .25s;
}
.ask-list details[open] { border-color: var(--orange); }

.ask-list summary {
  display: flex; justify-content: space-between; align-items: center;
  font-size: 15.5px; font-weight: 800;
}
.ask-list summary::after {
  content: "+";
  font-size: 20px;
  color: var(--orange);
  font-weight: 900;
  transition: transform .3s;
}
.ask-list details[open] summary::after { transform: rotate(45deg); }

.ask-list details p {
  margin-top: 10px;
  font-size: 14.5px;
  color: var(--ink-dim);
}

/* ===================== 底部转化 ===================== */
.final { padding: 78px 0; background: var(--bg-alt); }
.final-inner { text-align: center; max-width: 640px; }
.final h2 { font-size: clamp(24px, 3vw, 34px); font-weight: 900; }
.final p { margin: 14px 0 28px; color: var(--ink-dim); }

/* ===================== 页脚 ===================== */
.foot {
  border-top: 1px solid var(--line);
  padding: 30px 0 36px;
  background: var(--bg);
}
.foot-inner { text-align: center; font-size: 14px; color: var(--ink-dim); }
.foot-sub { margin-top: 4px; font-size: 12.5px; color: var(--ink-mute); }

/* ===================== 入场动画 ===================== */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ===================== 响应式 ===================== */
@media (max-width: 920px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .card-grid { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .scene-grid { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .menu { display: none; }
  .card-grid { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .hero { padding: 48px 0 60px; }
  .block { padding: 54px 0; }
}