:root {
  --primary: #2563eb; --primary-dark: #1d4ed8; --accent: #06b6d4;
  --dark: #0f172a; --gray: #64748b; --light: #f8fafc; --radius: 16px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif; color: var(--dark); background: var(--light); line-height: 1.7; }
img { max-width: 100%; height: auto; display: block; }
a { text-decoration: none; color: inherit; }
.container { max-width: 1120px; margin: 0 auto; padding: 0 24px; }

/* 导航 */
.site-nav { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,.92); backdrop-filter: blur(10px); border-bottom: 1px solid #e2e8f0; }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 17px; }
.logo-badge { width: 36px; height: 36px; border-radius: 10px; background: linear-gradient(135deg, var(--primary), var(--accent)); display: grid; place-items: center; font-size: 18px; }
.nav-links { display: flex; gap: 24px; font-size: 15px; color: var(--gray); align-items: center; list-style: none; }
.nav-links a:hover { color: var(--primary); }
@media (max-width: 768px) { .nav-links { display: none; } }

/* Hero */
.hero { background: radial-gradient(1000px 500px at 20% -10%, rgba(37,99,235,.15), transparent), radial-gradient(800px 400px at 90% 0%, rgba(6,182,212,.15), transparent), #fff; padding: 80px 0 90px; text-align: center; }
.hero-compact { padding: 48px 0; }
.hero-tag { display: inline-block; background: #eff6ff; color: var(--primary); border: 1px solid #bfdbfe; border-radius: 999px; padding: 6px 16px; font-size: 14px; font-weight: 600; margin-bottom: 20px; }
.hero h1 { font-size: clamp(30px, 5vw, 52px); font-weight: 900; line-height: 1.25; }
.hero h1 span { background: linear-gradient(90deg, var(--primary), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p { margin: 18px auto 30px; max-width: 620px; color: var(--gray); font-size: 17px; }
.hero-btns { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.btn { display: inline-block; padding: 13px 32px; border-radius: 999px; font-weight: 700; font-size: 15px; transition: .2s; }
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 10px 24px rgba(37,99,235,.3); }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); }
.btn-ghost { border: 1.5px solid #cbd5e1; color: var(--dark); background: #fff; }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary); }
.hero-stats { margin-top: 50px; display: flex; gap: 44px; justify-content: center; flex-wrap: wrap; }
.stat b { font-size: 28px; color: var(--primary); }
.stat span { display: block; font-size: 13px; color: var(--gray); }

/* 首屏二维码卡片 */
.hero-flex { display: flex; align-items: center; justify-content: center; gap: 48px; }
.hero-main { flex: 1; min-width: 0; }
.hero-qr { flex: none; }
.qr-card { background: #fff; border: 1px solid #e2e8f0; border-radius: 20px; padding: 20px; text-align: center; box-shadow: 0 16px 40px rgba(37,99,235,.12); }
.qr-card img { width: 180px; height: 180px; border-radius: 12px; margin: 0 auto 10px; }
.qr-card b { display: block; font-size: 16px; }
.qr-card span { display: block; font-size: 12.5px; color: var(--gray); margin-top: 4px; }
@media (max-width: 800px) {
  .hero-flex { flex-direction: column; }
  .hero-qr { order: -1; }
  .qr-card img { width: 150px; height: 150px; }
}

/* Section */
section { padding: 72px 0; }
.sec-head { text-align: center; margin-bottom: 44px; }
.sec-head .kicker { color: var(--primary); font-weight: 700; letter-spacing: 2px; font-size: 14px; }
.sec-head h2 { font-size: clamp(24px, 4vw, 34px); margin-top: 8px; }
.sec-head p { color: var(--gray); margin-top: 8px; }

/* 卡片 */
.grid { display: grid; gap: 22px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 900px) { .grid-3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .grid-2, .grid-3 { grid-template-columns: 1fr; } }
.card { background: #fff; border-radius: var(--radius); padding: 26px; border: 1px solid #e2e8f0; transition: .25s; display: block; }
.card:hover { transform: translateY(-5px); box-shadow: 0 16px 40px rgba(15,23,42,.08); border-color: #bfdbfe; }
.card .icon { width: 50px; height: 50px; border-radius: 14px; font-size: 24px; display: grid; place-items: center; margin-bottom: 14px; background: #eff6ff; }
.card h3 { font-size: 17px; margin: 10px 0 6px; }
.card p { font-size: 14px; color: var(--gray); }
.card-more { display: inline-block; margin-top: 12px; color: var(--primary); font-size: 14px; font-weight: 600; }
.card-thumb { border-radius: 12px; margin-bottom: 12px; width: 100%; object-fit: cover; aspect-ratio: 16/9; }
.thumb-placeholder { background: linear-gradient(135deg, #eff6ff, #ecfeff); display: grid; place-items: center; font-size: 36px; }

/* 关注公众号（大界面） */
.join-big { display: flex; align-items: center; justify-content: space-between; gap: 48px; flex-wrap: wrap; background: linear-gradient(135deg, #eff6ff, #ecfeff); border: 1px solid #bfdbfe; border-radius: 28px; padding: 64px 56px; box-shadow: 0 24px 60px rgba(15,23,42,.08); }
.join-big-left { flex: 1; min-width: 260px; }
.join-big h2 { font-size: clamp(26px, 4vw, 40px); line-height: 1.3; margin-top: 8px; }
.join-points { list-style: none; margin: 28px 0; }
.join-points li { padding: 10px 0; font-size: 17px; color: #334155; border-bottom: 1px dashed #cbd5e1; }
.join-points li:last-child { border-bottom: none; }
.join-points b { color: var(--primary); font-size: 24px; margin-right: 6px; }
.join-desc { color: var(--gray); font-size: 15.5px; }
.qr-big { flex: none; background: #fff; border: 2px solid #bfdbfe; border-radius: 24px; padding: 28px; text-align: center; box-shadow: 0 16px 40px rgba(37,99,235,.14); }
.qr-big img { width: 240px; height: 240px; border-radius: 16px; margin: 0 auto 14px; }
.qr-big b { display: block; font-size: 18px; }
.qr-big span { display: block; font-size: 13px; color: var(--gray); margin-top: 6px; }
@media (max-width: 800px) { .join-big { padding: 40px 24px; } .qr-big img { width: 200px; height: 200px; } }

/* 备案号 */
.beian { display: block; margin-top: 10px; font-size: 12.5px; color: #94a3b8; }
.beian:hover { color: #fff; }
.join-card { background: #fff; border-radius: 24px; padding: 48px 36px; display: flex; align-items: center; justify-content: space-between; gap: 36px; flex-wrap: wrap; box-shadow: 0 24px 60px rgba(15,23,42,.1); border: 1px solid #e2e8f0; }
.join-card h2 { font-size: clamp(22px, 3.5vw, 30px); }
.join-card p { color: var(--gray); margin-top: 10px; max-width: 480px; }
.qr-box { flex: none; width: 240px; text-align: center; border: 2px dashed #cbd5e1; border-radius: 20px; padding: 22px; background: var(--light); }
.qr-placeholder { width: 180px; height: 180px; margin: 0 auto 12px; border-radius: 14px; background: repeating-linear-gradient(0deg, #e2e8f0 0 10px, #fff 10px 20px), repeating-linear-gradient(90deg, #e2e8f0 0 10px, #fff 10px 20px); display: grid; place-items: center; font-size: 38px; }
.qr-box b { font-size: 15px; }
.qr-box span { display: block; font-size: 12.5px; color: var(--gray); margin-top: 4px; }

/* 文章页 */
.single-wrap { max-width: 760px; margin: 0 auto; padding: 56px 24px; }
.single-title { font-size: clamp(24px, 4vw, 34px); line-height: 1.35; }
.single-meta { color: var(--gray); font-size: 14px; margin: 12px 0 24px; }
.single-thumb { border-radius: 14px; margin-bottom: 24px; }
.single-content { font-size: 16.5px; }
.single-content h2, .single-content h3 { margin: 1.4em 0 .6em; }
.single-content p, .single-content ul, .single-content ol { margin: .8em 0; }
.single-content img { border-radius: 12px; margin: 1em auto; }
.single-content a { color: var(--primary); text-decoration: underline; }
.single-content blockquote { border-left: 4px solid var(--primary); padding: 8px 16px; background: #eff6ff; border-radius: 8px; margin: 1em 0; color: #334155; }

/* 布局与侧栏 */
.layout-with-sidebar { display: grid; grid-template-columns: 1fr 300px; gap: 36px; }
@media (max-width: 900px) { .layout-with-sidebar { grid-template-columns: 1fr; } }
.sidebar .widget { background: #fff; border: 1px solid #e2e8f0; border-radius: 14px; padding: 20px; margin-bottom: 20px; }
.widget-title { font-size: 16px; margin-bottom: 12px; }
.widget-list { list-style: none; }
.widget-list li { padding: 8px 0; border-bottom: 1px dashed #e2e8f0; font-size: 14.5px; }
.widget-list li:last-child { border-bottom: none; }
.widget-list a:hover { color: var(--primary); }

/* 分页 / 页脚 */
.pagination { margin-top: 36px; display: flex; justify-content: center; }
.pagination .page-numbers { padding: 8px 14px; border: 1px solid #e2e8f0; border-radius: 8px; margin: 0 4px; background: #fff; color: var(--gray); }
.pagination .current { background: var(--primary); color: #fff; border-color: var(--primary); }
.site-footer { background: var(--dark); color: #94a3b8; padding: 40px 0; font-size: 14px; }
.footer-inner { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
.footer-inner b { color: #fff; }
.footer-menu { list-style: none; display: flex; gap: 20px; }
.footer-menu a:hover { color: #fff; }

/* 单页广告模式 */
.ad-page { min-height: calc(100vh - 64px); display: flex; align-items: center; background: radial-gradient(1000px 500px at 20% -10%, rgba(37,99,235,.12), transparent), radial-gradient(800px 400px at 90% 10%, rgba(6,182,212,.12), transparent), #fff; }