/* ==========================================================================
   爱加速官网 — 网络连接加速工具
   工业风：钢铁灰 + 信号橙 + 深色 hero + 数据卡矩阵 + 套餐表
   ========================================================================== */

:root {
  --iron: #374151;
  --steel: #9ca3af;
  --signal: #f59e0b;
  --signal-dark: #d97706;
  --bg: #f3f4f6;
  --dark: #1f2937;
  --text: #111827;
  --muted: #6b7280;
  --white: #fff;
  --title: #111827;
  --body: #374151;
  --radius: 8px;
  --shadow: 0 2px 10px rgba(0,0,0,.05);
  --maxw: 1160px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
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: 1.7;
}
a { color: var(--signal-dark); text-decoration: none; transition: color .2s; }
a:hover { color: var(--signal); }
img { max-width: 100%; height: auto; display: block; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- 顶部工具条 ---------- */
.top-toolbar {
  background: var(--dark); color: var(--steel); padding: 8px 5%;
  display: flex; justify-content: space-between; font-size: 12px; flex-wrap: wrap; gap: 8px;
}
.top-toolbar span { color: var(--signal); font-weight: 600; }

/* ---------- 导航 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100; background: var(--white);
  border-bottom: 2px solid #e5e7eb;
}
.nav { display: flex; align-items: center; gap: 22px; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 800; color: var(--dark); }
.logo img, .f-logo img { flex: none; }
.logo em { font-style: normal; color: var(--signal); }
.nav-links { display: flex; gap: 4px; }
.nav-links a { padding: 7px 13px; border-radius: 4px; color: var(--text); font-size: 13px; font-weight: 600; letter-spacing: .5px; }
.nav-links a:hover { color: var(--signal); background: #fef3c7; }
.nav-links a.active { color: var(--signal-dark); background: #fef3c7; }
.nav-actions { margin-left: auto; display: flex; align-items: center; gap: 12px; }
.nav-login { color: var(--text); font-size: 14px; font-weight: 600; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 24px; border-radius: 4px; font-size: 14px; font-weight: 700;
  cursor: pointer; border: 1px solid transparent; transition: all .2s; white-space: nowrap;
}
.btn-primary { background: var(--signal); color: #1f2937; }
.btn-primary:hover { background: var(--signal-dark); color: #fff; }
.btn-outline { background: transparent; color: var(--signal); border: 2px solid var(--signal); }
.btn-outline:hover { background: rgba(245,158,11,.1); color: var(--signal-dark); }
.btn-lg { padding: 13px 30px; font-size: 15px; }
.btn-block { width: 100%; }

/* ---------- 深色工业 Hero（首页+内页统一深色底） ---------- */
.hero { background: var(--dark); color: #fff; padding: 40px 5%; }
.hero-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; max-width: var(--maxw); margin: 0 auto; }
.hero-badge {
  display: inline-block; background: rgba(245,158,11,.15); color: var(--signal);
  padding: 5px 14px; border-radius: 4px; font-size: 12px; font-weight: 700; margin-bottom: 16px; letter-spacing: .5px;
}
.hero h1 { font-size: 34px; font-weight: 800; line-height: 1.2; margin-bottom: 12px; color: #fff; }
.hero h1 .hl { color: var(--signal); }
.hero .sub { color: var(--steel); font-size: 16px; margin-bottom: 24px; line-height: 1.8; max-width: 520px; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; }
.hero-note { margin-top: 18px; font-size: 13px; color: var(--steel); display: flex; gap: 16px; flex-wrap: wrap; }
.hero-note span::before { content: "✓"; color: var(--signal); margin-right: 5px; font-weight: 700; }

/* 首页 hero 加宽 */
.hero.hero-home { padding: 60px 5%; }
.hero.hero-home h1 { font-size: 40px; }

/* 数据卡矩阵 2×2 */
.hero-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.hi-card { background: var(--iron); padding: 24px; border-radius: 8px; text-align: center; }
.hi-card .hi-icon { font-size: 30px; margin-bottom: 8px; }
.hi-card .hi-val { font-size: 24px; font-weight: 800; color: var(--signal); }
.hi-card .hi-lbl { font-size: 12px; color: var(--steel); }

/* ---------- 通用 section ---------- */
.section { padding: 60px 0; }
.section.alt { background: var(--white); border-top: 1px solid #e5e7eb; border-bottom: 1px solid #e5e7eb; }
.sec-head { text-align: center; max-width: 640px; margin: 0 auto 36px; }
.sec-head h2 { font-size: 26px; font-weight: 800; color: var(--title); }
.sec-head p { margin-top: 10px; color: var(--muted); font-size: 15px; }
.sec-head.left { text-align: left; margin-left: 0; }

/* ---------- 服务/套餐表 ---------- */
.svc-table { width: 100%; border-collapse: collapse; background: var(--white); border-radius: 8px; overflow: hidden; box-shadow: var(--shadow); }
.svc-table th { background: var(--dark); color: #fff; padding: 14px 16px; text-align: left; font-size: 13px; font-weight: 600; letter-spacing: .5px; }
.svc-table td { padding: 14px 16px; border-bottom: 1px solid #e5e7eb; font-size: 14px; }
.svc-table tr:hover td { background: #f9fafb; }
.svc-name { font-weight: 600; }
.svc-price { font-weight: 700; color: var(--signal-dark); }

/* ---------- 功能卡（用于首页场景） ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.feature-card {
  background: var(--white); border: 1px solid #e5e7eb; border-radius: 8px;
  padding: 24px; box-shadow: var(--shadow); transition: transform .2s;
}
.feature-card:hover { transform: translateY(-3px); }
.feature-card .ic { width: 50px; height: 50px; border-radius: 8px; display: flex; align-items: center; justify-content: center; background: #fef3c7; margin-bottom: 14px; }
.feature-card h3 { font-size: 17px; color: var(--title); margin-bottom: 6px; }
.feature-card p { font-size: 13px; color: var(--muted); }

/* ---------- 下载矩阵 ---------- */
.dl-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.dl-card {
  background: var(--white); border: 1px solid #e5e7eb; border-radius: 8px;
  padding: 26px; text-align: center; box-shadow: var(--shadow); transition: transform .2s;
}
.dl-card:hover { transform: translateY(-3px); }
.dl-card .ic { width: 56px; height: 56px; margin: 0 auto 14px; border-radius: 8px; background: #fef3c7; display: flex; align-items: center; justify-content: center; }
.dl-card h3 { font-size: 16px; color: var(--title); }
.dl-card p { font-size: 13px; color: var(--muted); margin: 8px 0 16px; }
.dl-card .badge { display: inline-block; font-size: 12px; color: var(--signal-dark); background: #fef3c7; padding: 3px 10px; border-radius: 4px; margin-bottom: 14px; }

/* ---------- 步骤 ---------- */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.step { display: flex; gap: 14px; }
.step .idx { flex: none; width: 40px; height: 40px; border-radius: 6px; background: var(--signal); color: #1f2937; font-weight: 800; font-size: 17px; display: flex; align-items: center; justify-content: center; }
.step h3 { font-size: 16px; color: var(--title); }
.step p { font-size: 13px; color: var(--muted); margin-top: 5px; }

/* ---------- 场景卡 ---------- */
.scene-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.scene-card { display: flex; gap: 14px; background: var(--white); border: 1px solid #e5e7eb; border-radius: 8px; padding: 22px; align-items: flex-start; box-shadow: var(--shadow); }
.scene-card .ic { flex: none; width: 44px; height: 44px; border-radius: 8px; background: #fef3c7; display: flex; align-items: center; justify-content: center; }
.scene-card h3 { font-size: 16px; color: var(--title); }
.scene-card p { font-size: 13px; color: var(--muted); margin-top: 5px; }

/* ---------- 订阅套餐 ---------- */
.plan-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; align-items: stretch; }
.plan {
  background: var(--white); border: 1px solid #e5e7eb; border-radius: 8px; padding: 28px;
  display: flex; flex-direction: column; position: relative; box-shadow: var(--shadow); transition: all .2s;
}
.plan:hover { transform: translateY(-3px); }
.plan.hot { border: 2px solid var(--signal); }
.plan .tag { position: absolute; top: -12px; left: 50%; transform: translateX(-50%); background: var(--signal); color: #1f2937; font-size: 11px; font-weight: 800; padding: 3px 14px; border-radius: 4px; }
.plan h3 { font-size: 17px; color: var(--title); }
.plan .price { margin: 14px 0 4px; font-size: 38px; font-weight: 800; color: var(--signal-dark); line-height: 1; }
.plan .price small { font-size: 14px; color: var(--muted); }
.plan .price-unit { font-size: 13px; color: var(--muted); }
.plan ul { list-style: none; margin: 20px 0 24px; flex: 1; }
.plan ul li { padding: 7px 0; font-size: 13px; color: var(--body); display: flex; gap: 8px; align-items: flex-start; }
.plan ul li::before { content: "✓"; color: var(--signal-dark); font-weight: 700; flex: none; }

/* ---------- FAQ ---------- */
.faq-list { max-width: 820px; margin: 0 auto; }
.faq-item { background: var(--white); border: 1px solid #e5e7eb; border-radius: 8px; margin-bottom: 12px; overflow: hidden; }
.faq-item details summary { padding: 16px 20px; cursor: pointer; font-weight: 600; color: var(--title); font-size: 15px; list-style: none; display: flex; justify-content: space-between; align-items: center; }
.faq-item details summary::-webkit-details-marker { display: none; }
.faq-item details summary::after { content: "+"; font-size: 20px; color: var(--signal-dark); font-weight: 400; }
.faq-item details[open] summary::after { content: "−"; }
.faq-item details .faq-a { padding: 0 20px 18px; font-size: 14px; color: var(--body); }

/* ---------- 正文 SEO 段 ---------- */
.seo-content { font-size: 15px; color: var(--body); text-align: justify; }
.seo-content p { margin-bottom: 14px; text-indent: 2em; }
.seo-content h2, .seo-content h3 { text-indent: 0; color: var(--title); margin: 22px 0 12px; }
.seo-content strong { color: var(--signal-dark); }

/* ---------- 文章页 ---------- */
.article { max-width: 820px; margin: 0 auto; }
.article-meta { color: var(--muted); font-size: 13px; margin: 14px 0 26px; display: flex; gap: 16px; flex-wrap: wrap; }
.article h2 { font-size: 22px; color: var(--title); margin: 28px 0 12px; }
.article h3 { font-size: 18px; color: var(--title); margin: 22px 0 10px; }
.article p { margin-bottom: 14px; text-align: justify; }
.article ul, .article ol { margin: 0 0 16px 22px; }
.article li { margin-bottom: 8px; }
.article strong { color: var(--signal-dark); }
.article .tip { background: #fef3c7; border-left: 4px solid var(--signal); padding: 16px 18px; border-radius: 6px; margin: 18px 0; }

/* ---------- 面包屑 ---------- */
.breadcrumb { font-size: 13px; color: var(--muted); padding: 18px 0 0; }
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--signal-dark); }
.breadcrumb span { margin: 0 6px; color: #d1d5db; }

/* 深色 hero 内的面包屑用浅灰 */
.hero .breadcrumb { color: var(--steel); }
.hero .breadcrumb a { color: var(--steel); }
.hero .breadcrumb a:hover { color: var(--signal); }
.hero .breadcrumb span { color: #4b5563; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--dark); color: var(--steel); padding: 48px 5% 30px; margin-top: 40px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 24px; max-width: var(--maxw); margin-left: auto; margin-right: auto; }
.footer-col .f-logo { display: flex; align-items: center; gap: 8px; color: #fff; font-size: 17px; font-weight: 700; margin-bottom: 14px; }
.footer-col p { font-size: 13px; color: var(--steel); line-height: 1.8; }
.footer-col h4 { color: #fff; font-size: 14px; margin-bottom: 12px; }
.footer-col a { display: block; color: var(--steel); font-size: 13px; padding: 5px 0; }
.footer-col a:hover { color: var(--signal); }
.footer-bottom { border-top: 1px solid var(--iron); padding-top: 20px; text-align: center; font-size: 12px; max-width: var(--maxw); margin: 0 auto; }

/* ---------- 404 ---------- */
.error-404 { text-align: center; padding: 90px 0 70px; }
.error-404 .code { font-size: 100px; font-weight: 800; color: var(--signal); line-height: 1; }
.error-404 h1 { font-size: 26px; color: var(--title); margin: 18px 0 10px; }
.error-404 p { color: var(--muted); margin-bottom: 28px; }

/* ---------- 响应式 ---------- */
@media (max-width: 768px) {
  .nav { gap: 14px; flex-wrap: wrap; height: auto; padding: 12px 0; }
  .nav-links { order: 3; width: 100%; overflow-x: auto; gap: 2px; }
  .nav-links a { white-space: nowrap; }
  .hero { padding: 40px 5%; }
  .hero-grid { grid-template-columns: 1fr; gap: 30px; }
  .hero h1 { font-size: 28px; }
  .feature-grid, .dl-grid, .plan-grid, .steps { grid-template-columns: 1fr 1fr; }
  .scene-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .sec-head h2 { font-size: 24px; }
}
@media (max-width: 480px) {
  .feature-grid, .dl-grid, .plan-grid, .steps { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 24px; }
  .hero-cta { flex-direction: column; }
  .hero-cta .btn { width: 100%; }
  body { font-size: 15px; }
  .hero-stats { grid-template-columns: 1fr 1fr; }
}