:root{
  --bg:#f6f7fb;
  --surface:#fff;
  --surface-2:#f0f3f8;
  --text:#172033;
  --muted:#667085;
  --line:#e4e8ef;
  --brand:#3056d3;
  --brand-2:#6c7cff;
  --brand-soft:#ebefff;
  --green:#157a57;
  --green-soft:#e7f6ef;
  --amber:#98651b;
  --amber-soft:#fff5dc;
  --red:#b42318;
  --red-soft:#ffebe7;
  --shadow:0 12px 40px rgba(25,37,64,.07);
  --shadow-sm:0 4px 16px rgba(25,37,64,.06);
  --radius:18px;
  --font:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  color-scheme:light;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:86px}
body{margin:0;background:var(--bg);color:var(--text);font:15px/1.75 var(--font);-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button,input,select{font:inherit}
button{cursor:pointer}
.container{width:min(1180px,calc(100% - 36px));margin:0 auto}
.topbar{position:sticky;top:0;z-index:50;background:rgba(246,247,251,.86);backdrop-filter:blur(14px);border-bottom:1px solid rgba(228,232,239,.92)}
.topbar-in{height:72px;display:flex;align-items:center;gap:18px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;letter-spacing:-.02em;white-space:nowrap}
.logo-mark{width:34px;height:34px;border-radius:11px;background:linear-gradient(135deg,var(--brand-2),var(--brand));display:grid;place-items:center;color:#fff;box-shadow:0 8px 18px rgba(48,86,211,.22)}
.logo-mark svg{width:18px;height:18px}
.logo small{display:block;font-size:11px;color:var(--muted);font-weight:600;letter-spacing:0}
.nav-links{display:flex;gap:6px;margin-left:16px}
.nav-links a{padding:9px 12px;border-radius:10px;color:var(--muted);font-weight:600;font-size:14px}
.nav-links a:hover{background:var(--surface);color:var(--text)}
.nav-actions{margin-left:auto;display:flex;gap:8px;align-items:center}
.icon-btn,.ghost-btn{border:1px solid var(--line);background:var(--surface);height:40px;border-radius:11px;padding:0 12px;color:var(--muted)}
.icon-btn:hover,.ghost-btn:hover{color:var(--text);border-color:#cdd5e4}
.hero{padding:66px 0 30px}
.hero-grid{display:grid;grid-template-columns:1.2fr .8fr;gap:28px;align-items:stretch}
.eyebrow{display:inline-flex;align-items:center;gap:7px;padding:7px 10px;border-radius:999px;background:var(--brand-soft);color:var(--brand);font-size:12px;font-weight:800;letter-spacing:.03em}
.hero h1{font-size:clamp(36px,5vw,62px);line-height:1.08;letter-spacing:-.045em;margin:17px 0 16px;max-width:760px}
.hero h1 span{color:var(--brand)}
.hero-copy{color:var(--muted);font-size:18px;max-width:700px;margin:0 0 24px}
.hero-meta{display:flex;gap:18px;flex-wrap:wrap;color:var(--muted);font-size:13px}
.hero-meta strong{color:var(--text)}
.hero-panel{background:linear-gradient(145deg,#10182e,#1e2a57);border-radius:26px;padding:26px;color:#fff;box-shadow:0 24px 60px rgba(16,24,46,.22);position:relative;overflow:hidden}
.hero-panel:before{content:"";position:absolute;width:210px;height:210px;border-radius:50%;background:radial-gradient(circle,rgba(108,124,255,.45),transparent 68%);top:-85px;right:-80px}
.panel-label{font-size:12px;color:rgba(255,255,255,.68);letter-spacing:.08em;text-transform:uppercase}
.panel-title{font-size:24px;font-weight:800;line-height:1.25;margin:8px 0 18px;position:relative}
.stat-row{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}
.stat-card{padding:14px;background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.11);border-radius:15px}
.stat-num{font-size:24px;font-weight:800}.stat-name{font-size:12px;color:rgba(255,255,255,.66);margin-top:2px}
.search-shell{margin-top:26px;background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:10px;display:flex;gap:8px;box-shadow:var(--shadow-sm)}
.search-shell input{flex:1;border:0;outline:0;padding:12px 13px;background:transparent;font-size:16px;min-width:0}
.search-shell button{border:0;background:var(--brand);color:#fff;border-radius:12px;padding:0 18px;font-weight:700}
.quick-tags{display:flex;gap:8px;overflow:auto;padding:12px 2px 2px;scrollbar-width:none}.quick-tags::-webkit-scrollbar{display:none}
.quick-tag{flex:0 0 auto;border:1px solid var(--line);background:var(--surface);border-radius:999px;padding:7px 12px;font-size:12px;color:var(--muted)}
.quick-tag:hover{border-color:#c7d0df;color:var(--text)}
.section{padding:28px 0 18px}.section + .section{padding-top:44px}
.section-head{display:flex;align-items:end;justify-content:space-between;gap:16px;margin-bottom:16px}.section-head h2{font-size:28px;letter-spacing:-.03em;margin:0}.section-head p{margin:4px 0 0;color:var(--muted);font-size:14px}.section-head a{font-size:13px;color:var(--brand);font-weight:700}
.category-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.category-card{background:var(--surface);border:1px solid var(--line);border-radius:17px;padding:18px;transition:.2s ease;box-shadow:0 1px 0 rgba(25,37,64,.02)}
.category-card:hover{transform:translateY(-2px);box-shadow:var(--shadow);border-color:#d3dbea}
.category-top{display:flex;align-items:start;justify-content:space-between;gap:10px}.category-no{color:var(--muted);font-size:12px;font-weight:800}.category-card h3{margin:4px 0 7px;font-size:17px;line-height:1.35}.category-card p{margin:0;color:var(--muted);font-size:13px;line-height:1.65;display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden}
.pill{display:inline-flex;align-items:center;gap:5px;white-space:nowrap;border-radius:999px;padding:5px 9px;font-size:11px;font-weight:800;background:var(--surface-2);color:var(--muted)}
.pill.blue{background:var(--brand-soft);color:var(--brand)}.pill.green{background:var(--green-soft);color:var(--green)}.pill.amber{background:var(--amber-soft);color:var(--amber)}.pill.red{background:var(--red-soft);color:var(--red)}
.featured{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.feature{background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:20px;box-shadow:var(--shadow-sm)}
.feature h3{font-size:18px;line-height:1.45;margin:12px 0 8px}.feature p{margin:0;color:var(--muted);font-size:14px}.feature .tags{display:flex;gap:7px;flex-wrap:wrap;margin-top:16px}
.tool-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.tool{background:linear-gradient(180deg,#fff,#f8f9fc);border:1px solid var(--line);border-radius:17px;padding:18px}.tool-icon{width:36px;height:36px;border-radius:11px;background:var(--brand-soft);color:var(--brand);display:grid;place-items:center;font-weight:800}.tool h3{font-size:16px;margin:11px 0 5px}.tool p{font-size:13px;color:var(--muted);margin:0}
.explain{display:grid;grid-template-columns:1fr 1fr;gap:16px}.explain-card{background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:20px}.explain-card h3{margin:0 0 8px;font-size:18px}.explain-card p{margin:0;color:var(--muted);font-size:14px}
.results{padding:28px 0 70px;display:none}.results.on{display:block}.results-head{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:14px}.results-head h2{margin:0;font-size:22px}.results-count{color:var(--muted);font-size:13px}.result-list{display:grid;gap:12px}.result-card{background:var(--surface);border:1px solid var(--line);border-radius:15px;padding:16px}.result-top{display:flex;align-items:start;gap:10px}.result-card h3{margin:0;font-size:16px;line-height:1.45;flex:1}.result-card p{color:var(--muted);margin:8px 0}.result-meta{display:flex;gap:6px;flex-wrap:wrap}
.detail-shell{display:none;padding:28px 0 70px}.detail-shell.on{display:block}.detail-head{margin-bottom:18px}.detail-head .back{display:inline-flex;color:var(--brand);font-weight:700;font-size:13px;margin-bottom:10px}.detail-head h1{font-size:36px;line-height:1.15;margin:0 0 8px;letter-spacing:-.03em}.detail-head p{margin:0;color:var(--muted);max-width:800px}.entry-grid{display:grid;grid-template-columns:1fr 320px;gap:16px}.entries{display:grid;gap:12px}.entry{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:18px}.entry h3{font-size:17px;line-height:1.45;margin:0 0 10px}.entry .human{padding:11px 13px;border-radius:11px;background:var(--brand-soft);color:var(--text);margin:0 0 10px}.entry dl{display:grid;grid-template-columns:84px 1fr;gap:8px 12px;margin:0}.entry dt{color:var(--muted);font-size:12px}.entry dd{margin:0;font-size:13px}.aside{position:sticky;top:90px;align-self:start}.aside-card{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:16px}.aside-card + .aside-card{margin-top:12px}.aside-card h3{margin:0 0 9px;font-size:14px}.aside-card p{margin:0;color:var(--muted);font-size:13px}.source-link{display:inline-block;margin-top:9px;color:var(--brand);font-size:12px;font-weight:700}
.footer{padding:34px 0 50px;border-top:1px solid var(--line);color:var(--muted)}.footer-grid{display:grid;grid-template-columns:1fr auto;gap:22px;align-items:start}.footer strong{color:var(--text)}.footer small{display:block;margin-top:7px;max-width:850px;line-height:1.7}.footer-links{display:flex;gap:14px;flex-wrap:wrap}.footer-links a{font-size:13px;color:var(--muted)}.footer-links a:hover{color:var(--text)}
.modal-backdrop{position:fixed;inset:0;background:rgba(7,12,28,.46);backdrop-filter:blur(4px);z-index:100;display:none;align-items:center;justify-content:center;padding:16px}.modal-backdrop.on{display:flex}.modal{width:min(900px,100%);max-height:min(82vh,860px);overflow:auto;background:var(--surface);border-radius:22px;border:1px solid var(--line);box-shadow:0 30px 90px rgba(7,12,28,.25);padding:26px}.modal-head{display:flex;justify-content:space-between;gap:12px;align-items:center}.modal h2{margin:0;font-size:24px}.close{width:38px;height:38px;border-radius:10px;border:1px solid var(--line);background:var(--surface-2)}.modal-body{margin-top:12px}.modal-body h3{margin:20px 0 7px}.modal-body p,.modal-body li{color:var(--muted);font-size:14px}.modal-body ul{padding-left:20px}
@media (max-width:1000px){.hero-grid{grid-template-columns:1fr}.category-grid{grid-template-columns:repeat(2,1fr)}.featured{grid-template-columns:1fr}.tool-grid{grid-template-columns:repeat(2,1fr)}.entry-grid{grid-template-columns:1fr}.aside{position:static}}
@media (max-width:720px){.container{width:min(100% - 22px,680px)}.topbar-in{height:64px}.nav-links{display:none}.hero{padding:42px 0 22px}.hero h1{font-size:40px}.hero-copy{font-size:16px}.category-grid{grid-template-columns:1fr}.tool-grid{grid-template-columns:1fr 1fr}.stat-row{grid-template-columns:1fr 1fr 1fr}.search-shell button{padding:0 13px}.section-head{display:block}.section-head a{display:inline-block;margin-top:7px}.detail-head h1{font-size:30px}.footer-grid{grid-template-columns:1fr}.hero-panel{padding:22px}}
@media (max-width:480px){.tool-grid{grid-template-columns:1fr}.stat-card{padding:12px}.stat-num{font-size:20px}.hero h1{font-size:34px}.search-shell input{font-size:15px}}

/* SEO/GEO topic pages */
.topic-hero{padding:38px 0 24px;background:linear-gradient(180deg,#eef2ff 0%,var(--bg) 100%);border-bottom:1px solid var(--line)}
.breadcrumbs{display:flex;gap:8px;align-items:center;color:var(--muted);font-size:12px;margin-bottom:18px}.breadcrumbs a{color:var(--brand);font-weight:700}.topic-kicker{display:flex;gap:8px;align-items:center;color:var(--muted);font-size:12px;font-weight:800}.topic-hero h1{font-size:clamp(34px,5vw,56px);letter-spacing:-.045em;line-height:1.1;margin:12px 0 10px;max-width:920px}.topic-question{font-size:21px;line-height:1.55;margin:0;max-width:920px;font-weight:750}.topic-desc{margin:10px 0 0;color:var(--muted);line-height:1.75;max-width:900px}.topic-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:18px}.topic-actions .ghost-btn{display:inline-flex;align-items:center;text-decoration:none}.topic-body{padding-top:24px}.topic-layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:18px}.topic-toolbar{position:sticky;top:76px;z-index:4;display:flex;justify-content:space-between;align-items:center;gap:14px;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(12px);padding:10px 0;margin-bottom:12px}.topic-toolbar strong{font-size:20px}.topic-toolbar label{display:flex;align-items:center;gap:8px;color:var(--muted);font-size:12px}.topic-toolbar input{width:min(360px,45vw);border:1px solid var(--line);border-radius:10px;background:var(--surface);padding:9px 11px;outline:none;color:var(--text)}.topic-toolbar input:focus{border-color:var(--brand)}.entry{scroll-margin-top:92px}.entry-top{display:flex;justify-content:space-between;gap:10px;align-items:center;margin-bottom:7px}.entry-kicker{color:var(--muted);font-size:12px;font-weight:800}.entry h2{font-size:20px;line-height:1.45;margin:0 0 12px;letter-spacing:-.02em}.entry-chips{display:flex;gap:6px;flex-wrap:wrap;margin:10px 0}.entry dd a{color:var(--brand)}.inline-link{color:var(--brand);font-weight:750}.topic-q{margin-top:12px;padding-top:11px;border-top:1px dashed var(--line);font-size:12px;color:var(--muted);line-height:1.6}.directory-hero{padding-top:52px}.directory-hero h1{font-size:clamp(36px,5vw,60px);letter-spacing:-.045em;line-height:1.08;margin:13px 0}.directory-stats{display:flex;gap:22px;flex-wrap:wrap;color:var(--muted);font-size:13px;margin-top:18px}.directory-stats strong{color:var(--text);font-size:18px;margin-right:3px}
body[data-theme="dark"] .topic-hero{background:linear-gradient(180deg,#171d31 0%,var(--bg) 100%)}
@media (max-width:900px){.topic-layout{grid-template-columns:1fr}.topic-toolbar{position:static}.aside{position:static}.topic-question{font-size:18px}}
@media (max-width:640px){.topic-toolbar{display:block}.topic-toolbar label{display:block;margin-top:8px}.topic-toolbar input{width:100%;box-sizing:border-box}.topic-hero{padding-top:28px}.topic-hero h1{font-size:36px}.topic-question{font-size:17px}.topic-actions{align-items:stretch}.topic-actions>*{width:100%;justify-content:center}.directory-hero{padding-top:36px}}