:root{
  --blue:#4285F4; --ink:#1a1a1a; --muted:#6b7280; --line:#e5e7eb; --bg:#fff;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0; color:var(--ink); background:var(--bg);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  line-height:1.75; font-size:17px;
}
.wrap{max-width:760px; margin:0 auto; padding:0 18px}
a{color:var(--blue); text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%; height:auto; display:block}
h1,h2,h3{line-height:1.3; font-weight:700; margin:1.6em 0 .6em}
h1{font-size:30px; margin-top:.4em}
h2{font-size:23px; border-left:4px solid var(--blue); padding-left:10px}
h3{font-size:19px}
p{margin:.8em 0}
blockquote{margin:1em 0; padding:10px 16px; background:#f5f8ff; border-left:3px solid var(--blue); color:#374151}
pre{background:#0f172a; color:#e2e8f0; padding:14px; border-radius:8px; overflow:auto; font-size:14px}
code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace}
hr{border:none; border-top:1px solid var(--line); margin:2em 0}

.site-header{background:#fff; border-bottom:1px solid var(--line); position:sticky; top:0; z-index:10}
.site-header .wrap{display:flex; align-items:center; justify-content:space-between; height:56px}
.brand{font-weight:800; color:var(--ink); font-size:18px}
.site-header nav a{margin-left:16px; color:var(--muted); font-size:15px}

.breadcrumb{color:var(--muted); font-size:14px; margin:18px 0 0}
.breadcrumb a{color:var(--muted)}
.meta{color:var(--muted); font-size:14px; margin:.4em 0 1.4em}
.lead{font-size:18px; color:#374151}

.cta{margin:2.4em 0 1em; padding:22px; background:#f5f8ff; border:1px solid #dbeafe; border-radius:12px}
.cta h2{margin-top:0; border:none; padding:0; font-size:20px}
.btn{display:inline-block; background:var(--blue); color:#fff; padding:10px 18px; border-radius:8px; font-weight:600}
.btn:hover{text-decoration:none; opacity:.92}

.grid{display:grid; gap:16px; margin-top:1.2em}
.card{border:1px solid var(--line); border-radius:12px; padding:18px}
.card .cat{display:inline-block; font-size:12px; color:var(--blue); background:#eef4ff; padding:2px 8px; border-radius:99px; margin-bottom:8px}
.card h3{margin:.2em 0 .3em; font-size:19px}
.card h3 a{color:var(--ink)}
.card .desc{color:var(--muted); font-size:15px; margin:.3em 0}
.card .meta{color:var(--muted); font-size:13px}

.site-footer{border-top:1px solid var(--line); margin-top:3em; padding:24px 0; text-align:center}
.site-footer p{margin:.2em 0; font-size:14px}
.muted{color:var(--muted)}

@media (max-width:600px){
  body{font-size:16px}
  h1{font-size:25px} h2{font-size:20px}
  .wrap{padding:0 14px}
}