:root{
  --max-width:1240px;
  --carbon:#15161c;
  --midnight:#1b2540;
  --midnight-deep:#121a30;
  --silver:#7d8592;
  --violet:#6c5ce7;
  --cyan:#22c1d6;
  --warm:#f7f5f0;
  --red:#c0392b;
  --orange:#d97a2b;
  --text:#1b1e24;
  --muted:#5c636d;
  --border:#e2e3e8;
  --card:#ffffff;
  --bg:#f7f7f8;
}
*{box-sizing:border-box;}
body{margin:0;font-family:"PingFang SC","Microsoft YaHei","Segoe UI",Arial,sans-serif;color:var(--text);background:var(--bg);line-height:1.75;font-size:16px;}
a{color:var(--midnight);text-decoration:none;}
a:hover{text-decoration:underline;}
img,svg{max-width:100%;display:block;}
.wrap{max-width:var(--max-width);margin:0 auto;padding:0 22px;}

header.site-header{background:var(--carbon);border-bottom:1px solid #262832;position:sticky;top:0;z-index:60;}
.topbar{display:flex;align-items:center;justify-content:space-between;padding:14px 0;}
.brand{display:flex;align-items:center;gap:10px;font-size:19px;font-weight:800;color:#fff;letter-spacing:.5px;}
.brand .mark{width:36px;height:36px;border-radius:6px;background:linear-gradient(135deg,var(--violet),var(--cyan));display:flex;align-items:center;justify-content:center;color:#fff;font-size:14px;font-weight:900;}
nav.mainnav ul{list-style:none;display:flex;gap:18px;margin:0;padding:0;flex-wrap:wrap;}
nav.mainnav a{font-size:13.5px;color:#c7cad2;font-weight:600;}
nav.mainnav a.active,nav.mainnav a:hover{color:var(--cyan);text-decoration:none;}
.header-cta{display:flex;gap:10px;}
.btn{display:inline-block;padding:9px 16px;border-radius:5px;font-size:13.5px;font-weight:700;}
.btn-primary{background:var(--violet);color:#fff;}
.btn-primary:hover{background:#5a49d6;text-decoration:none;}
.btn-ghost{border:1px solid #3a3c46;color:#dfe0e6;}
.btn-ghost:hover{border-color:var(--cyan);text-decoration:none;}

.breadcrumb{font-size:12.5px;color:var(--muted);padding:12px 0;}
.breadcrumb a{color:var(--muted);}

.hero{background:linear-gradient(180deg,var(--midnight-deep),var(--midnight) 65%,#16203c);color:#e8eaf0;padding:40px 0 30px;}
.hero h1{font-size:26px;margin:0 0 12px;color:#fff;}
.hero p.lead{font-size:15px;color:#b7bccb;max-width:900px;margin:0;}
.hero .tagline{font-size:12.5px;letter-spacing:2px;color:var(--cyan);text-transform:uppercase;margin-bottom:10px;font-weight:700;}

main{padding:32px 0 54px;}
section.block{margin-bottom:38px;}
section.block h2{font-size:20px;border-left:4px solid var(--violet);padding-left:10px;margin:0 0 14px;color:var(--midnight-deep);}
section.block h3{font-size:16.5px;margin:18px 0 8px;color:var(--midnight);}
section.block p{margin:0 0 12px;color:#2c2f36;}

.grid{display:grid;gap:16px;}
.grid-2{grid-template-columns:1fr 1fr;}
.grid-3{grid-template-columns:repeat(3,1fr);}
.grid-4{grid-template-columns:repeat(4,1fr);}
@media(max-width:900px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr 1fr;}}
@media(max-width:640px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr;}nav.mainnav ul{gap:10px;}}

.card{background:var(--card);border:1px solid var(--border);border-radius:8px;padding:16px;}
.card h4{margin:0 0 6px;font-size:15px;}
.card .meta{font-size:12px;color:var(--muted);margin-bottom:6px;}
.card p{font-size:13.5px;color:#4b4f57;margin:0;}

.taglist{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0 0;}
.tag{font-size:12.5px;background:#eeecfb;color:var(--midnight-deep);border-radius:14px;padding:4px 10px;}

table.plain{width:100%;border-collapse:collapse;font-size:13.5px;}
table.plain th,table.plain td{border:1px solid var(--border);padding:8px 10px;text-align:left;}
table.plain th{background:#f0f0f3;}

.faq dt{font-weight:700;margin-top:14px;color:var(--midnight-deep);}
.faq dd{margin:4px 0 0;color:#3c3f47;}

.related{background:#f0f0f3;border-radius:8px;padding:16px 18px;}
.related ul{margin:8px 0 0;padding-left:18px;}

.col3{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;}
@media(max-width:900px){.col3{grid-template-columns:1fr;}}
.col-head{font-size:12px;letter-spacing:1.5px;text-transform:uppercase;font-weight:800;margin-bottom:10px;padding-bottom:6px;border-bottom:2px solid var(--border);}
.col-head.trend{color:var(--orange);border-color:var(--orange);}
.col-head.ai{color:var(--violet);border-color:var(--violet);}
.col-head.tech{color:var(--cyan);border-color:var(--cyan);}
.col-head.problem{color:var(--red);border-color:var(--red);}

.fitgrid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;}
@media(max-width:900px){.fitgrid{grid-template-columns:1fr 1fr;}}
@media(max-width:640px){.fitgrid{grid-template-columns:1fr;}}
.fitcard{background:#fff;border:1px solid var(--border);border-radius:8px;padding:14px;font-size:13.5px;}
.fitcard b{display:block;color:var(--midnight-deep);margin-bottom:4px;font-size:14px;}

footer.site-footer{background:var(--carbon);color:#c7cad2;padding:36px 0 22px;margin-top:44px;}
footer.site-footer a{color:#c7cad2;}
footer.site-footer .cols{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:20px;}
footer.site-footer h5{font-size:13.5px;margin:0 0 10px;color:#fff;}
footer.site-footer ul{list-style:none;margin:0;padding:0;font-size:12.5px;line-height:2;}
footer.site-footer .bottom{border-top:1px solid #262832;margin-top:20px;padding-top:14px;font-size:12px;color:#8b8f99;}
@media(max-width:900px){footer.site-footer .cols{grid-template-columns:1fr 1fr;}}

.article-body h2{font-size:19px;margin:26px 0 10px;color:var(--midnight-deep);}
.article-body h3{font-size:16px;margin:16px 0 8px;}
.article-body p{color:#2b2e35;margin:0 0 13px;}
.article-body ul,.article-body ol{color:#2b2e35;margin:0 0 13px;padding-left:20px;}
.article-meta{font-size:12.5px;color:var(--muted);margin-bottom:18px;}
.notice{background:#fbf3e7;border:1px solid #e8c99a;color:#6b4a12;border-radius:6px;padding:12px 16px;font-size:13px;margin:0 0 20px;}
.notice.blue{background:#eaecf7;border-color:#c3c8ea;color:#232a52;}

figure.diagram{margin:0 0 20px;text-align:center;}
figure.diagram figcaption{font-size:12.5px;color:var(--muted);margin-top:8px;}

#assistant-log{border:1px solid var(--border);border-radius:8px;background:#fff;height:320px;overflow-y:auto;padding:14px;margin-bottom:12px;}
.assistant-msg{margin-bottom:14px;}
.assistant-msg p{margin:0 0 4px;font-size:13.5px;padding:8px 12px;border-radius:8px;display:inline-block;max-width:90%;}
.assistant-msg.bot p{background:#eeecfb;color:#232a52;}
.assistant-msg.user{text-align:right;}
.assistant-msg.user p{background:var(--violet);color:#fff;}
.assistant-msg a{font-size:12.5px;display:block;margin-top:2px;}
#assistant-form{display:flex;gap:8px;}
#assistant-input{flex:1;padding:10px 12px;border:1px solid var(--border);border-radius:6px;font-size:14px;}
#assistant-form button{padding:10px 18px;border:none;border-radius:6px;background:var(--violet);color:#fff;font-weight:700;cursor:pointer;}
#assistant-form button:hover{background:#5a49d6;}