/* ============================================================
   乌云互联 SEO 引导站 · 全站样式
   ============================================================ */
:root {
  --c-primary: #1b3f8f;
  --c-primary-2: #2f6fe4;
  --c-accent: #ff6a2c;
  --c-accent-2: #ff914d;
  --c-ink: #0e1a33;
  --c-text: #3c4866;
  --c-muted: #77839d;
  --c-bg: #f5f7fc;
  --c-card: #ffffff;
  --c-line: #e4e9f3;
  --c-dark: #0a1730;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 10px 30px rgba(15, 27, 51, 0.07);
  --shadow-lg: 0 24px 60px rgba(15, 27, 51, 0.16);
  --max: 1180px;
  --font: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui,
    -apple-system, "Segoe UI", Roboto, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font);
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.75;
  font-size: 16px;
  overflow-x: hidden;
}
img, svg { max-width: 100%; }
a { color: var(--c-primary-2); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--c-accent); }
h1, h2, h3, h4 { color: var(--c-ink); line-height: 1.35; font-weight: 800; }
ul, ol { list-style: none; }

.container { width: min(100% - 40px, var(--max)); margin-inline: auto; }

/* ---------------- 按钮 ---------------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 22px; border-radius: 999px; font-weight: 700; font-size: 15px;
  border: 1px solid transparent; cursor: pointer; white-space: nowrap;
  transition: transform 0.18s, box-shadow 0.18s, background 0.18s, color 0.18s;
}
.btn-sm { padding: 8px 16px; font-size: 13.5px; }
.btn-lg { padding: 15px 30px; font-size: 16px; }
.btn-primary {
  background: linear-gradient(135deg, var(--c-accent), var(--c-accent-2));
  color: #fff;
  box-shadow: 0 10px 24px rgba(255, 106, 44, 0.32);
}
.btn-primary:hover { color: #fff; transform: translateY(-2px); box-shadow: 0 14px 30px rgba(255, 106, 44, 0.42); }
.btn-ghost { background: transparent; color: var(--c-primary); border-color: rgba(27, 63, 143, 0.35); }
.btn-ghost:hover { color: var(--c-primary); border-color: var(--c-primary); background: rgba(27, 63, 143, 0.06); }
.hero .btn-ghost, .cta-band .btn-ghost { color: #fff; border-color: rgba(255, 255, 255, 0.45); background: rgba(255, 255, 255, 0.06); }
.hero .btn-ghost:hover, .cta-band .btn-ghost:hover { color: #fff; border-color: #fff; background: rgba(255, 255, 255, 0.16); }

/* ---------------- 顶栏 ---------------- */
.site-header {
  position: sticky; top: 0; z-index: 60;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--c-line);
}
.header-inner { display: flex; align-items: center; gap: 22px; height: 72px; }
.logo { display: inline-flex; align-items: center; gap: 10px; flex: 0 0 auto; }
.logo-mark {
  width: 42px; height: 42px; border-radius: 12px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--c-primary), var(--c-primary-2));
  color: #fff; font-weight: 900; font-size: 20px; letter-spacing: -1px;
  box-shadow: 0 8px 18px rgba(27, 63, 143, 0.28);
}
.logo-text { display: flex; flex-direction: column; line-height: 1.15; }
.logo-text strong { color: var(--c-ink); font-size: 19px; letter-spacing: 0.5px; }
.logo-text em { font-style: normal; font-size: 11px; color: var(--c-muted); letter-spacing: 2px; text-transform: uppercase; }

.main-nav { margin-left: auto; }
.main-nav > ul { display: flex; align-items: center; gap: 4px; }
.main-nav > ul > li { position: relative; }
.main-nav > ul > li > a {
  display: inline-flex; align-items: center; gap: 5px;
  padding: 10px 14px; border-radius: 10px; color: var(--c-ink);
  font-weight: 600; font-size: 15px;
}
.main-nav > ul > li.active > a, .main-nav > ul > li > a:hover { color: var(--c-primary); background: rgba(27, 63, 143, 0.07); }
.caret { width: 6px; height: 6px; border-right: 1.6px solid currentColor; border-bottom: 1.6px solid currentColor; transform: rotate(45deg) translateY(-2px); opacity: 0.7; }

.main-nav li.has-sub > ul.sub {
  position: absolute; top: calc(100% + 10px); left: 50%; transform: translateX(-50%) translateY(8px);
  width: 288px; padding: 10px; border-radius: 14px; background: #fff;
  box-shadow: var(--shadow-lg); border: 1px solid var(--c-line);
  display: grid; gap: 2px; opacity: 0; visibility: hidden; pointer-events: none;
  transition: opacity 0.2s, transform 0.2s, visibility 0.2s;
}
.main-nav li.has-sub:hover > ul.sub { opacity: 1; visibility: visible; pointer-events: auto; transform: translateX(-50%) translateY(0); }
.main-nav li.has-sub > ul.sub li a { display: block; padding: 9px 12px; border-radius: 9px; font-size: 14px; color: var(--c-ink); font-weight: 600; }
.main-nav li.has-sub > ul.sub li a em { display: block; font-style: normal; font-weight: 400; font-size: 12px; color: var(--c-muted); margin-top: 1px; }
.main-nav li.has-sub > ul.sub li a:hover { background: rgba(47, 111, 228, 0.08); color: var(--c-primary); }

.header-cta { display: flex; align-items: center; gap: 10px; margin-left: 10px; }

.nav-toggle {
  display: none; width: 44px; height: 40px; border: 1px solid var(--c-line); border-radius: 10px;
  background: #fff; flex-direction: column; justify-content: center; align-items: center; gap: 4px; cursor: pointer;
}
.nav-toggle span { width: 18px; height: 2px; background: var(--c-ink); border-radius: 2px; transition: 0.25s; }
body.nav-open .nav-toggle span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
body.nav-open .nav-toggle span:nth-child(2) { opacity: 0; }
body.nav-open .nav-toggle span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ---------------- Hero ---------------- */
.hero {
  position: relative; overflow: hidden; color: #eaf1ff;
  background:
    radial-gradient(900px 420px at 15% -10%, rgba(47, 111, 228, 0.42), transparent 60%),
    radial-gradient(700px 380px at 85% 10%, rgba(255, 106, 44, 0.28), transparent 62%),
    linear-gradient(160deg, #0b1a38 0%, #12295c 55%, #0a1730 100%);
  padding: 76px 0 84px;
}
.hero::after {
  content: ""; position: absolute; inset: 0;
  background-image: linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 44px 44px; pointer-events: none;
  mask-image: radial-gradient(circle at 50% 0%, #000 40%, transparent 78%);
}
.hero-inner { position: relative; z-index: 1; max-width: 880px; }
.eyebrow {
  display: inline-block; margin-bottom: 16px; padding: 5px 14px; border-radius: 999px;
  font-size: 13px; font-weight: 700; letter-spacing: 0.5px; color: #ffd9c4;
  background: rgba(255, 106, 44, 0.16); border: 1px solid rgba(255, 106, 44, 0.38);
}
.hero h1 { font-size: clamp(28px, 4.4vw, 48px); color: #fff; letter-spacing: 0.5px; margin-bottom: 18px; }
.hero-lead { font-size: clamp(15px, 1.6vw, 18px); color: #c9d6f0; max-width: 760px; margin-bottom: 30px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 26px; }
.hero-badges { display: flex; flex-wrap: wrap; gap: 10px; }
.hero-badges li {
  font-size: 13px; color: #cfe0ff; padding: 7px 14px; border-radius: 999px;
  background: rgba(255, 255, 255, 0.07); border: 1px solid rgba(255, 255, 255, 0.14);
}
.hero-note { margin-top: 18px; font-size: 12.5px; color: #8fa4cc; }

/* ---------------- 面包屑 ---------------- */
.breadcrumb { background: #fff; border-bottom: 1px solid var(--c-line); }
.breadcrumb ol { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; padding: 12px 0; font-size: 13px; color: var(--c-muted); }
.breadcrumb li { display: flex; align-items: center; gap: 8px; }
.breadcrumb li + li::before { content: "/"; color: #c3ccdd; }
.breadcrumb a { color: var(--c-muted); }
.breadcrumb a:hover { color: var(--c-primary); }

/* ---------------- 区块 ---------------- */
.site-main { padding-bottom: 10px; }
.sec { padding: 64px 0; }
.sec:nth-child(even) { background: #fff; }
.sec-head { max-width: 760px; margin-bottom: 38px; }
.sec-head.center { margin-inline: auto; text-align: center; }
.sec-head h2 { font-size: clamp(22px, 2.6vw, 30px); margin-bottom: 10px; }
.sec-head p { color: var(--c-muted); }

/* ---------------- 网格卡片 ---------------- */
.grid { display: grid; gap: 20px; }
.grid.cards { grid-template-columns: repeat(4, 1fr); }
.grid.cards.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.feats { grid-template-columns: repeat(3, 1fr); }

.card {
  position: relative; background: var(--c-card); border: 1px solid var(--c-line);
  border-radius: var(--radius); padding: 26px 24px; box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  display: flex; flex-direction: column;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: rgba(47, 111, 228, 0.35); }
.card h3 { font-size: 17px; margin: 14px 0 8px; }
.card h3 a { color: var(--c-ink); }
.card h3 a:hover { color: var(--c-primary); }
.card p { font-size: 14px; color: var(--c-muted); flex: 1; }
.card .more { margin-top: 16px; font-size: 13.5px; font-weight: 700; color: var(--c-primary-2); }
.card .more:hover { color: var(--c-accent); }
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 12px; }
.tags li { font-size: 12px; color: var(--c-primary); background: rgba(47, 111, 228, 0.09); padding: 3px 9px; border-radius: 999px; }

.ico { display: inline-grid; place-items: center; width: 46px; height: 46px; border-radius: 13px;
  background: linear-gradient(135deg, rgba(47, 111, 228, 0.12), rgba(255, 106, 44, 0.1));
  color: var(--c-primary); }
.ico svg { width: 23px; height: 23px; }

.feat { background: #fff; border: 1px solid var(--c-line); border-radius: var(--radius); padding: 26px 24px; box-shadow: var(--shadow); }
.feat h3 { font-size: 17px; margin: 14px 0 8px; }
.feat p { font-size: 14px; color: var(--c-muted); }

/* ---------------- 价格表 ---------------- */
.table-wrap { overflow-x: auto; border-radius: var(--radius); border: 1px solid var(--c-line); background: #fff; box-shadow: var(--shadow); }
.price-table { width: 100%; border-collapse: collapse; min-width: 640px; font-size: 14.5px; }
.price-table th, .price-table td { padding: 14px 18px; text-align: left; border-bottom: 1px solid var(--c-line); }
.price-table thead th { background: #f2f6ff; color: var(--c-ink); font-weight: 700; white-space: nowrap; }
.price-table tbody tr:last-child td { border-bottom: 0; }
.price-table tbody tr:hover { background: #fafcff; }
.price-table tr.hl { background: #fff7f2; }
.price-table tr.hl td:first-child { box-shadow: inset 3px 0 0 var(--c-accent); }
.table-note { margin-top: 12px; font-size: 12.5px; color: var(--c-muted); }

/* ---------------- FAQ ---------------- */
.faq-list { display: grid; gap: 12px; max-width: 900px; }
.faq-item { background: #fff; border: 1px solid var(--c-line); border-radius: var(--radius-sm); padding: 4px 20px; }
.faq-item summary { display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 16px 0; cursor: pointer; font-weight: 700; color: var(--c-ink); list-style: none; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-icon { position: relative; flex: 0 0 auto; width: 18px; height: 18px; }
.faq-icon::before, .faq-icon::after { content: ""; position: absolute; inset: 50% 0 auto; height: 2px; background: var(--c-primary); border-radius: 2px; transform: translateY(-50%); transition: 0.25s; }
.faq-icon::after { transform: translateY(-50%) rotate(90deg); }
.faq-item[open] .faq-icon::after { transform: translateY(-50%) rotate(0); }
.faq-item[open] summary { color: var(--c-primary); }
.faq-body { padding: 0 0 18px; font-size: 14.5px; color: var(--c-text); }

/* ---------------- 步骤 / 数据 ---------------- */
.steps { display: grid; gap: 16px; counter-reset: step; }
.steps li { display: flex; gap: 18px; background: #fff; border: 1px solid var(--c-line); border-radius: var(--radius-sm); padding: 20px 22px; }
.step-num { flex: 0 0 36px; width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center;
  font-weight: 800; color: #fff; background: linear-gradient(135deg, var(--c-primary), var(--c-primary-2)); }
.steps h3 { font-size: 16px; margin-bottom: 4px; }
.steps p { font-size: 14px; color: var(--c-muted); }

.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.stats li { background: #fff; border: 1px solid var(--c-line); border-radius: var(--radius); padding: 26px 20px; text-align: center; box-shadow: var(--shadow); }
.stats strong { display: block; font-size: clamp(24px, 3vw, 34px); color: var(--c-primary); letter-spacing: -0.5px; }
.stats span { font-size: 13.5px; color: var(--c-muted); }

/* ---------------- CTA ---------------- */
.cta-band { background: linear-gradient(135deg, #10224a, #1b3f8f 60%, #22336e); color: #eaf1ff; padding: 56px 0; }
.cta-inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 26px; }
.cta-text h2 { color: #fff; font-size: clamp(21px, 2.4vw, 28px); margin-bottom: 8px; }
.cta-text p { color: #c3d2ef; font-size: 15px; }
.cta-actions { display: flex; flex-wrap: wrap; gap: 12px; }

/* ---------------- 正文 ---------------- */
.prose { max-width: 900px; }
.prose p { margin-bottom: 14px; }
.prose h2 { font-size: 22px; margin: 30px 0 12px; }
.prose h3 { font-size: 18px; margin: 22px 0 8px; }
.prose ul, .prose ol { margin: 0 0 16px 22px; }
.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }
.prose li { margin-bottom: 6px; }
.prose strong { color: var(--c-ink); }
.prose .tip { background: #fff8f3; border-left: 4px solid var(--c-accent); padding: 14px 18px; border-radius: 8px; margin: 18px 0; font-size: 14.5px; }

.article-head { max-width: 900px; margin-bottom: 26px; }
.article-head .meta { display: flex; flex-wrap: wrap; gap: 14px; font-size: 13px; color: var(--c-muted); margin-top: 12px; }
.article-head .meta span { display: inline-flex; align-items: center; gap: 6px; }
.article-body { max-width: 900px; }
.article-body h2 { font-size: 22px; margin: 34px 0 12px; padding-left: 12px; border-left: 4px solid var(--c-accent); }
.article-body h3 { font-size: 18px; margin: 24px 0 10px; }
.article-body p { margin-bottom: 14px; }
.article-body ul, .article-body ol { margin: 0 0 16px 24px; }
.article-body ul { list-style: disc; }
.article-body ol { list-style: decimal; }
.article-body li { margin-bottom: 6px; }
.article-body .tip { background: #fff8f3; border-left: 4px solid var(--c-accent); padding: 14px 18px; border-radius: 8px; margin: 20px 0; }

/* ---------------- 页脚 ---------------- */
.site-footer { background: #0a1730; color: #9fb0d0; padding: 56px 0 0; margin-top: 10px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr 1fr; gap: 34px; padding-bottom: 40px; }
.footer-brand p { font-size: 13.5px; margin-top: 14px; max-width: 320px; }
.footer-brand .license { color: #7f90b3; font-size: 12.5px; }
.footer-col h4 { color: #eaf1ff; font-size: 14px; margin-bottom: 14px; letter-spacing: 0.5px; }
.footer-col ul { display: grid; gap: 9px; }
.footer-col a { color: #9fb0d0; font-size: 13.5px; }
.footer-col a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid rgba(255, 255, 255, 0.08); padding: 20px 0 26px; }
.footer-bottom .container { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 10px; font-size: 12.5px; color: #7f90b3; }
.footer-bottom a { color: #9fb0d0; text-decoration: underline; }

/* ---------------- 返回顶部 ---------------- */
.back-top {
  position: fixed; right: 22px; bottom: 24px; z-index: 70;
  width: 44px; height: 44px; border-radius: 50%; display: grid; place-items: center;
  background: rgba(27, 63, 143, 0.9); color: #fff; font-size: 18px; box-shadow: var(--shadow-lg);
  opacity: 0; visibility: hidden; transition: 0.25s;
}
body.scrolled .back-top { opacity: 1; visibility: visible; }

/* ---------------- 响应式 ---------------- */
@media (max-width: 1080px) {
  .grid.cards { grid-template-columns: repeat(2, 1fr); }
  .grid.feats { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1.5fr 1fr 1fr; }
}
@media (max-width: 900px) {
  .nav-toggle { display: flex; margin-left: auto; }
  .header-cta { display: none; }
  .main-nav {
    position: absolute; top: 100%; left: 0; right: 0; margin-left: 0;
    background: #fff; border-bottom: 1px solid var(--c-line);
    max-height: 0; overflow: hidden; transition: max-height 0.3s ease;
  }
  .main-nav > ul { flex-direction: column; align-items: stretch; gap: 0; padding: 8px 20px 16px; }
  .main-nav > ul > li > a { padding: 12px 8px; }
  .main-nav li.has-sub > ul.sub {
    position: static; transform: none; width: auto; box-shadow: none; border: 0;
    padding: 0 0 6px 14px; opacity: 1; visibility: visible; pointer-events: auto; display: none;
  }
  .main-nav li.has-sub.open > ul.sub { display: grid; }
  body.nav-open .main-nav { max-height: 80vh; overflow-y: auto; }
  .stats { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 720px) {
  .grid.cards, .grid.feats { grid-template-columns: 1fr; }
  .sec { padding: 46px 0; }
  .hero { padding: 54px 0 60px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 24px; }
  .cta-inner { flex-direction: column; align-items: flex-start; }
}