/* ---------- 设计变量 ---------- */
:root{
  --brand:#0b4fd8; --brand-600:#083aa8; --brand-050:#eef4ff;
  --ink:#111827; --ink-2:#374151; --muted:#6b7280;
  --line:#e5e7eb; --line-2:#f3f4f6;
  --bg:#fff; --bg-soft:#f9fafb;
  --accent:#f59e0b; --accent-soft:#fff7e6;
  --radius:12px; --radius-sm:8px;
  --shadow-sm:0 1px 2px rgba(16,24,40,.05);
  --maxw:1100px; /* 页面整体收窄，更聚焦 */
  --header-h:64px;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%; scroll-behavior:smooth}
body{
  margin:0; background:var(--bg); color:var(--ink);
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Microsoft YaHei",sans-serif;
  font-size:15px; line-height:1.6;
}
img{max-width:100%; display:block}
a{color:var(--brand); text-decoration:none}
a:hover{color:var(--brand-600)}
h1,h2,h3{margin:0; font-weight:700;}
p{margin:0}
ul,ol{margin:0; padding:0; list-style:none}
.wrap{max-width:var(--maxw); margin:0 auto; padding:0 20px}

/* ---------- 顶部导航 ---------- */
.site-header{
  position:sticky; top:0; z-index:40; background:rgba(255,255,255,.95);
  backdrop-filter:saturate(180%) blur(8px); border-bottom:1px solid var(--line);
}
.header-inner{display:flex; align-items:center; gap:16px; height:var(--header-h)}
.brand{display:flex; align-items:center; gap:10px; flex:0 0 auto; color:var(--ink)}
.brand-logo-img{width:108px; height:32px; border-radius:8px; object-fit:contain;}
.brand-name{font-size:18px; font-weight:800;}
.brand-name small{display:block; font-size:11px; color:var(--muted); font-weight:500; letter-spacing:1px;}
.primary-nav{display:flex; align-items:center; gap:4px; margin-left:10px;}
.primary-nav a{padding:8px 12px; border-radius:6px; font-size:14px; font-weight:600; color:var(--ink-2);}
.primary-nav a.active{color:var(--brand); background:var(--brand-050);}
.primary-nav a:hover{background:var(--bg-soft); color:var(--brand)}
.header-actions{margin-left:auto; display:flex; align-items:center; gap:8px}
.btn{
  display:inline-flex; align-items:center; justify-content:center; gap:6px;
  padding:8px 16px; border-radius:6px; border:1px solid transparent; font-size:14px; font-weight:600;
  cursor:pointer; transition:all .15s ease;
}
.btn-primary{background:var(--brand); color:#fff}
.btn-primary:hover{background:var(--brand-600); color:#fff}
.btn-ghost{border-color:var(--line); color:var(--ink-2); background:#fff}
.btn-ghost:hover{border-color:var(--brand); color:var(--brand)}
.nav-toggle{display:none; background:none; border:none; font-size:20px; color:var(--ink); cursor:pointer;}

/* ---------- Hero 搜索区 ---------- */
.hero{padding:40px 0 30px; border-bottom:1px solid var(--line-2); background:var(--bg-soft);}
.hero-grid{display:grid; grid-template-columns:minmax(0,1fr) 300px; gap:32px; align-items:start;}
.hero-title{font-size:28px; margin-bottom:8px; letter-spacing:-.5px;}
.hero-title em{font-style:normal; color:var(--brand);}
.hero-sub{color:var(--muted); font-size:14px; margin-bottom:20px;}

/* 搜索框 */
.search-row{display:flex; gap:8px; max-width:680px;}
.search-field{flex:1; position:relative;}
.search-input{
  width:100%; height:48px; padding:0 16px 0 40px; font-size:15px;
  border:1px solid var(--line); border-radius:var(--radius); outline:none; background:#fff;
  transition:border-color .15s;
}
.search-input:focus{border-color:var(--brand); box-shadow:0 0 0 3px var(--brand-050);}
.search-field i{position:absolute; left:14px; top:50%; transform:translateY(-50%); color:var(--muted); font-size:15px;}
.search-submit{height:48px; padding:0 24px; border-radius:var(--radius); font-size:15px;}

.hot-terms{margin-top:12px; display:flex; flex-wrap:wrap; gap:8px; font-size:13px;align-items: baseline;}
.hot-terms span{color:var(--muted);}
.hot-terms a{color:var(--ink-2); background:#fff; border:1px solid var(--line); padding:2px 10px; border-radius:20px;}
.hot-terms a:hover{border-color:var(--brand); color:var(--brand);}

/* 排行榜卡片 */
.hero-card{background:#fff; border:1px solid var(--line); border-radius:var(--radius); overflow:hidden;}
.hero-card-head{padding:14px 16px; border-bottom:1px solid var(--line); background:#fff; display:flex; align-items:center; gap:8px;}
.hero-card-head h2{font-size:15px; margin:0;}
.hero-card-head i{color:#ef4444;}
.hero-rank-list{padding:12px 16px; display:flex; flex-direction:column; gap:12px;}
.hero-rank-list li{display:flex; align-items:center; gap:10px;}
.rank-num{width:18px; height:18px; line-height:18px; text-align:center; font-size:11px; font-weight:700; border-radius:4px; background:var(--bg-soft); color:var(--muted);}
.rank-1{background:#f59e0b; color:#fff;} .rank-2{background:#9ca3af; color:#fff;} .rank-3{background:#d97706; color:#fff;}
.rank-title{font-size:13px; font-weight:500; color:var(--ink); display:-webkit-box; -webkit-line-clamp:1; -webkit-box-orient:vertical; overflow:hidden; flex:1;}
.rank-title:hover{color:var(--brand);}
.rank-meta{font-size:11px; color:var(--muted);}

/* ---------- 热门技术领域 ---------- */
.section{padding:30px 0;}
.section-head{display:flex; align-items:center; justify-content:space-between; margin-bottom:20px;}
.section-head h2{font-size:20px;}
.section-head .more{font-size:13px; color:var(--muted);}
.section-head .more:hover{color:var(--brand);}

.topics-grid{display:grid; grid-template-columns:repeat(4,1fr); gap:12px;}
.topic{
  display:flex; align-items:center; gap:10px; padding:12px 16px;
  background:#fff; border:1px solid var(--line); border-radius:var(--radius);
  transition:border-color .15s;
}
.topic:hover{border-color:var(--brand);}
.topic i{font-size:18px; color:var(--brand); width:24px; text-align:center;}
.topic-txt b{display:block; font-size:14px; color:var(--ink);}
.topic-txt span{font-size:12px; color:var(--muted);}

/* ---------- 专利列表 ---------- */
.patent-list{display:flex; flex-direction:column; gap:10px;}
.patent{
  display:flex; align-items:center; gap:16px; padding:16px;
  background:#fff; border:1px solid var(--line); border-radius:var(--radius);
  transition:border-color .15s;
}
.patent:hover{border-color:var(--brand);}
.patent-thumb{width:240px; height:150px; border-radius:6px; background:var(--bg-soft); flex-shrink:0; overflow:hidden;}
.patent-thumb img{width:100%; height:100%; object-fit:cover;}
.patent-body{flex:1; min-width:0;}
.patent-body a h1{font-size:16px; margin-bottom:6px; white-space:nowrap; overflow:hidden; text-overflow:ellipsis;}
.patent-body a h1{color:var(--ink);}
.patent-body a h1:hover{color:var(--brand);}
.patent-body p{font-size:13px;color:#888;margin-bottom:10px;}
.patent-meta{display:flex; align-items:center; gap:12px; font-size:12px; color:var(--muted);}
.tag{padding:2px 8px; border-radius:4px; background:var(--brand-050); color:var(--brand);}
.tag-type{background:var(--accent-soft); color:#b45309;}
.patent-action .btn{padding:6px 14px; font-size:13px;}

/* 查看更多按钮 */
.load-more-wrap{text-align:center; margin-top:24px;}
.btn-load-more{padding:10px 32px; border-radius:var(--radius); font-size:14px;}

/* ---------- CTA 通栏 ---------- */
.cta-band{
  display:flex; align-items:center; justify-content:space-between; gap:20px; flex-wrap:wrap;
  margin:30px 0; padding:24px 28px; border-radius:var(--radius);
  background:var(--brand); color:#fff;
}
.cta-text h2{font-size:20px; margin-bottom:4px;}
.cta-text p{font-size:13px; opacity:.9;}
.cta-actions{display:flex; gap:10px;}
.cta-actions .btn-white{background:#fff; color:var(--brand);}
.cta-actions .btn-white:hover{background:var(--brand-050);}
.cta-actions .btn-outline{border-color:rgba(255,255,255,.4); color:#fff;}
.cta-actions .btn-outline:hover{background:rgba(255,255,255,.1);}

/* ---------- 页脚 ---------- */
.site-footer{border-top:1px solid var(--line); padding:24px 0; background:var(--bg-soft); font-size:13px; color:var(--muted); text-align:center;}

/* ============================================================
   响应式布局
   ============================================================ */
@media (max-width:860px){
  .hero-grid{grid-template-columns:1fr;}
  .hero-card{margin-top:20px;}
  .topics-grid{grid-template-columns:repeat(2,1fr);}
  
  .primary-nav{display:none;}
  .nav-toggle{display:block; margin-left:auto;}
  .header-actions .btn-text{display:none;}
  .header-actions .btn{width:36px; height:36px; padding:0; border-radius:50%;}
  
  .patent{flex-direction:column; align-items:flex-start; gap:12px; position:relative;}
  .patent-thumb{width:100%; height:160px;}
  .patent-body h3{white-space:normal; line-height:1.4;}
  .patent-action{width:100%; text-align:right;}
  
  .cta-band{flex-direction:column; align-items:flex-start; padding:20px;}
  .cta-actions{width:100%;}
  .cta-actions .btn{flex:1;}
}

@media (max-width:560px){
  .hero-title{font-size:24px;}
  .search-row{flex-direction:column;}
  .search-submit{width:100%;}
  .topics-grid{grid-template-columns:1fr;}
  .patent-meta{flex-wrap:wrap; gap:8px;}
}