/* ============================================================
   AutoGain — 设计系统 (Design System)
   轻主题 / 专业可信 / 高转化落地页
   配色：靛蓝主色 + 青绿点缀（与"自动化增收"语义呼应）
   ============================================================ */
:root {
  --bg: #f7f9fc;
  --surface: #ffffff;
  --surface-2: #eef2f8;
  --ink: #16202e;
  --ink-soft: #4a5870;
  --ink-faint: #8290a6;
  --primary: #3b5bdb;       /* 靛蓝 */
  --primary-dark: #2f49b0;
  --accent: #0ca678;        /* 青绿 */
  --accent-soft: #e6f7f1;
  --warn: #e8590c;
  --line: #e2e8f1;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 10px 30px rgba(22,32,46,.08);
  --shadow-sm: 0 4px 14px rgba(22,32,46,.06);
  --maxw: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
.muted { color: var(--ink-soft); }
.faint { color: var(--ink-faint); }
.center { text-align: center; }
.mono { font-family: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace; }

/* ---------- 顶栏 ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.86);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { font-weight: 800; font-size: 19px; letter-spacing: -.3px; }
.brand .dot { color: var(--accent); }
.nav-links { display: flex; gap: 22px; align-items: center; }
.nav-links a { color: var(--ink-soft); font-weight: 600; font-size: 15px; }
.nav-links a:hover { color: var(--primary); text-decoration: none; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block; cursor: pointer; border: none;
  font-weight: 700; font-size: 15px; font-family: var(--font);
  padding: 13px 26px; border-radius: 999px;
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 8px 20px rgba(59,91,219,.32); }
.btn-primary:hover { background: var(--primary-dark); color: #fff; }
.btn-accent { background: var(--accent); color: #fff; box-shadow: 0 8px 20px rgba(12,166,120,.3); }
.btn-accent:hover { color: #fff; filter: brightness(1.05); }
.btn-ghost { background: transparent; color: var(--primary); border: 1.5px solid var(--line); }
.btn-ghost:hover { border-color: var(--primary); }
.btn-lg { padding: 16px 34px; font-size: 16px; }

/* ---------- Hero ---------- */
.hero { padding: 72px 0 56px; }
.hero .eyebrow {
  display: inline-block; font-size: 13px; font-weight: 700; letter-spacing: .5px;
  color: var(--accent); background: var(--accent-soft);
  padding: 5px 13px; border-radius: 999px; margin-bottom: 18px;
}
.hero h1 {
  font-size: 44px; line-height: 1.18; letter-spacing: -.6px;
  font-weight: 800; margin-bottom: 18px;
}
.hero h1 .hl { color: var(--primary); }
.hero p.lead { font-size: 19px; color: var(--ink-soft); max-width: 640px; margin: 0 auto 30px; }
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero-note { margin-top: 16px; font-size: 13px; color: var(--ink-faint); }

/* ---------- 区块 ---------- */
section { padding: 56px 0; }
.section-head { text-align: center; margin-bottom: 40px; }
.section-head h2 { font-size: 32px; font-weight: 800; letter-spacing: -.4px; margin-bottom: 10px; }
.section-head p { color: var(--ink-soft); font-size: 17px; }
.surface { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); }
.divider { border: none; border-top: 1px solid var(--line); margin: 0; }

/* ---------- 痛点 / 卡片网格 ---------- */
.grid { display: grid; gap: 18px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px;
  box-shadow: var(--shadow-sm);
}
.card h3 { font-size: 18px; margin-bottom: 8px; }
.card p { color: var(--ink-soft); font-size: 15px; }
.card .ico { font-size: 26px; margin-bottom: 12px; display: block; }

/* ---------- 数据条 ---------- */
.stats { display: flex; gap: 36px; justify-content: center; flex-wrap: wrap; text-align: center; }
.stat .num { font-size: 38px; font-weight: 800; color: var(--primary); letter-spacing: -1px; }
.stat .lbl { color: var(--ink-soft); font-size: 14px; }

/* ---------- 步骤 ---------- */
.steps { counter-reset: s; }
.step { display: flex; gap: 18px; align-items: flex-start; padding: 18px 0; border-bottom: 1px dashed var(--line); }
.step:last-child { border-bottom: none; }
.step .n {
  flex: 0 0 42px; height: 42px; border-radius: 50%;
  background: var(--primary); color: #fff; font-weight: 800;
  display: grid; place-items: center; font-size: 18px;
}
.step h4 { font-size: 17px; margin-bottom: 4px; }
.step p { color: var(--ink-soft); font-size: 15px; }

/* ---------- 定价 ---------- */
.price-card { text-align: center; padding: 32px 26px; }
.price-card.featured { border: 2px solid var(--primary); box-shadow: var(--shadow); position: relative; }
.price-card .tag {
  position: absolute; top: -13px; left: 50%; transform: translateX(-50%);
  background: var(--primary); color: #fff; font-size: 12px; font-weight: 700;
  padding: 4px 14px; border-radius: 999px;
}
.price-card .amount { font-size: 40px; font-weight: 800; color: var(--ink); }
.price-card .amount small { font-size: 16px; color: var(--ink-faint); font-weight: 600; }
.price-card ul { list-style: none; text-align: left; margin: 20px 0; }
.price-card li { padding: 7px 0 7px 26px; position: relative; color: var(--ink-soft); font-size: 15px; }
.price-card li::before { content: "✓"; position: absolute; left: 0; color: var(--accent); font-weight: 800; }

/* ---------- 内容页 / 文章 ---------- */
.article { max-width: 760px; margin: 0 auto; padding: 48px 22px 80px; }
.article h1 { font-size: 34px; line-height: 1.25; margin-bottom: 12px; letter-spacing: -.4px; }
.article .meta { color: var(--ink-faint); font-size: 14px; margin-bottom: 28px; }
.article h2 { font-size: 24px; margin: 38px 0 12px; letter-spacing: -.3px; }
.article h3 { font-size: 19px; margin: 26px 0 10px; }
.article p { margin-bottom: 16px; color: #243042; }
.article ul, .article ol { margin: 0 0 18px 22px; }
.article li { margin-bottom: 8px; color: #243042; }
.article blockquote {
  border-left: 4px solid var(--primary); background: var(--surface-2);
  padding: 14px 18px; border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 0 0 18px; color: var(--ink-soft);
}
.article pre {
  background: #0f1726; color: #e6edf6; padding: 16px 18px; border-radius: var(--radius-sm);
  overflow: auto; font-size: 13.5px; margin: 0 0 18px; line-height: 1.6;
}
.article code { font-family: ui-monospace, Menlo, Consolas, monospace; }
.article :not(pre) > code { background: var(--surface-2); padding: 2px 6px; border-radius: 5px; font-size: 14px; color: var(--primary-dark); }
.callout {
  background: var(--accent-soft); border: 1px solid #b6e6d4; border-radius: var(--radius-sm);
  padding: 16px 18px; margin: 0 0 20px; color: #1d5c45;
}
.prompt-box {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm);
  padding: 14px 16px; margin: 0 0 14px; box-shadow: var(--shadow-sm);
}
.prompt-box .t { font-weight: 700; font-size: 15px; margin-bottom: 6px; }
.prompt-box .p { font-family: ui-monospace, Menlo, Consolas, monospace; font-size: 13.5px; color: #243042; background: var(--surface-2); padding: 10px 12px; border-radius: 8px; white-space: pre-wrap; }

/* ---------- FAQ ---------- */
.faq { max-width: 760px; margin: 0 auto; }
.faq details { border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 4px 18px; margin-bottom: 12px; background: var(--surface); }
.faq summary { cursor: pointer; font-weight: 700; padding: 14px 0; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; float: right; color: var(--primary); font-size: 20px; }
.faq details[open] summary::after { content: "−"; }
.faq p { color: var(--ink-soft); padding-bottom: 14px; }

/* ---------- 页脚 ---------- */
.footer { background: #0f1726; color: #c7d0de; padding: 44px 0 30px; margin-top: 30px; }
.footer a { color: #9db4d8; }
.footer .cols { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 30px; }
.footer h4 { color: #fff; font-size: 15px; margin-bottom: 12px; }
.footer p, .footer li { color: #9aa7bb; font-size: 14px; }
.footer ul { list-style: none; }
.footer li { padding: 5px 0; }
.footer .bottom { border-top: 1px solid #1e293b; margin-top: 30px; padding-top: 18px; font-size: 13px; color: #6b7891; }

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 33px; }
  .nav-links { display: none; }
  .footer .cols { grid-template-columns: 1fr; }
  .stats { gap: 22px; }
}