/* =====================================================================
   SEO知识分类页 · news_seo.css
   模块原创设计：左图右文服务带 / 序号水印卡片列表 + 侧栏 / 三原则图标卡
   ===================================================================== */

.banner-news{background-image:url('../images/banner-news.jpg')}

/* ---------- SEO 服务引导带 ---------- */
.seo-band{padding-bottom:20px;background:var(--c-white)}
.band-wrap{display:grid;grid-template-columns:1fr 1.25fr;gap:56px;align-items:center}
.band-media{position:relative}
.band-media img{border-radius:var(--radius-lg);aspect-ratio:3/2;object-fit:cover;box-shadow:var(--shadow-lg)}
.band-text h2{font-size:clamp(23px,2.8vw,32px);margin:6px 0 18px;line-height:1.4}
.band-text p{color:var(--c-text-2);margin-bottom:14px}
.band-text .btn{margin-top:8px}

/* ---------- 序号水印卡片列表 ---------- */
.seo-sec{background:var(--c-ice-2);padding-top:60px}
.seo-layout{display:grid;grid-template-columns:1fr 340px;gap:40px;align-items:start}
.num-wrap{display:grid;gap:22px}
.num-card{
  position:relative;display:grid;grid-template-columns:220px 1fr;gap:26px;background:#fff;
  border-radius:var(--radius-lg);padding:20px;box-shadow:var(--shadow);align-items:center;
  overflow:hidden;transition:transform var(--trans),box-shadow var(--trans);
}
.num-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.num-card::after{
  content:"SEO";position:absolute;right:14px;bottom:-14px;font-size:64px;font-weight:800;line-height:1;
  color:var(--c-ice);pointer-events:none;user-select:none;letter-spacing:1px;
}
.num-thumb{display:block;border-radius:12px;overflow:hidden;position:relative;z-index:1}
.num-thumb img{aspect-ratio:3/2;object-fit:cover;width:100%;transition:transform .6s}
.num-card:hover .num-thumb img{transform:scale(1.06)}
.num-body{position:relative;z-index:1;padding:4px 8px 4px 0}
.num-body a{
  font-size:18px;font-weight:700;color:var(--c-primary);line-height:1.5;display:block;margin-bottom:8px;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;
}
.num-card:hover .num-body a{color:var(--c-accent)}
.num-body p{
  font-size:13.5px;color:var(--c-text-2);line-height:1.75;margin-bottom:10px;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;
}
.num-body time{font-size:12.5px;color:var(--c-muted)}

/* ---------- 侧栏 ---------- */
.seo-side{display:grid;gap:26px;position:sticky;top:100px}
.side-box{background:#fff;border-radius:var(--radius-lg);box-shadow:var(--shadow);padding:22px}
.side-img{padding:0;overflow:hidden}
.side-img img{width:100%;aspect-ratio:16/10;object-fit:cover}
.side-img-cap{padding:22px}
.side-img-cap b{font-size:17px;color:var(--c-primary);display:block;margin-bottom:6px}
.side-img-cap p{font-size:13.5px;color:var(--c-muted);margin-bottom:14px}
.side-title{font-size:17px;margin-bottom:18px;padding-bottom:12px;position:relative;border-bottom:1px solid var(--c-line)}
.side-title::after{content:"";position:absolute;left:0;bottom:-1px;width:44px;height:3px;background:var(--c-grad);border-radius:3px}
.hot-list{display:grid;gap:14px}
.hot-list li{display:grid;gap:4px}
.hot-list a{display:flex;gap:10px;align-items:flex-start;font-size:14px;font-weight:600;line-height:1.6;color:var(--c-text)}
.hot-list a:hover{color:var(--c-accent)}
.hot-list b{
  flex-shrink:0;width:22px;height:22px;border-radius:7px;background:var(--c-ice);color:var(--c-accent);
  font-size:12.5px;font-weight:800;display:flex;align-items:center;justify-content:center;margin-top:2px;
}
.hot-list li:nth-child(1) b,.hot-list li:nth-child(2) b,.hot-list li:nth-child(3) b{background:var(--c-grad);color:#fff}
.hot-list time{font-size:12.5px;color:var(--c-muted);padding-left:32px}
.tag-cloud{display:flex;flex-wrap:wrap;gap:10px}
.tag-cloud a{font-size:13px;color:var(--c-text-2);background:var(--c-ice-2);border:1px solid var(--c-line);padding:6px 14px;border-radius:999px;transition:all var(--trans)}
.tag-cloud a:hover{background:var(--c-grad);color:#fff;border-color:transparent}

/* ---------- 优化三原则 ---------- */
.rule-sec{background:var(--c-white)}
.rule-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:26px}
.rule-card{
  background:var(--c-ice-2);border-radius:var(--radius-lg);padding:36px 30px;text-align:center;
  transition:all var(--trans);border-bottom:4px solid transparent;
}
.rule-card:hover{background:#fff;box-shadow:var(--shadow-lg);border-bottom-color:var(--c-accent);transform:translateY(-6px)}
.rule-icon{
  width:64px;height:64px;border-radius:50%;background:var(--c-grad);margin:0 auto 20px;
  display:flex;align-items:center;justify-content:center;box-shadow:0 10px 22px rgba(37,99,235,.3);
}
.rule-icon svg{width:28px;height:28px;fill:#fff}
.rule-card h3{font-size:19px;margin-bottom:10px}
.rule-card p{font-size:14px;color:var(--c-text-2);line-height:1.8;margin:0}

.contact-sec{padding-top:20px;background:var(--c-ice-2)}
.mobile-nav-body>a.active{color:var(--c-accent)!important;background:var(--c-ice)}

/* ---------- 响应式 ---------- */
@media (max-width:1080px){
  .seo-layout{grid-template-columns:1fr}
  .seo-side{position:static;grid-template-columns:1fr 1fr}
  .side-img{grid-column:1/-1}
}
@media (max-width:900px){
  .band-wrap{grid-template-columns:1fr;gap:32px}
  .num-card{grid-template-columns:160px 1fr;gap:18px}
  .rule-grid{grid-template-columns:1fr;max-width:480px;margin:0 auto}
  .seo-side{grid-template-columns:1fr}
}
@media (max-width:560px){
  .num-card{grid-template-columns:1fr}
}