:root{
  --bg:#f5f7fa; --card:#fff; --text:#1f2937; --muted:#6b7280;
  --border:#e5e7eb; --primary:#2563eb; --primary-soft:#eff6ff;
  --ok:#059669; --err:#dc2626; --radius:12px;
}
*{box-sizing:border-box}
body{
  margin:0;background:var(--bg);color:var(--text);line-height:1.65;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
}
a{color:var(--primary);text-decoration:none}
a:hover{text-decoration:underline}
header{
  background:linear-gradient(135deg,#1e3a8a,#2563eb);
  color:#fff;padding:18px 24px;
}
.header-inner{max-width:1080px;margin:0 auto;display:flex;align-items:center;gap:14px}
.logo{
  width:42px;height:42px;border-radius:11px;background:rgba(255,255,255,.16);
  display:grid;place-items:center;font-size:21px;flex:0 0 auto;
}
header h1{margin:0;font-size:19px;letter-spacing:.4px;color:#fff}
header h1 a{color:#fff;text-decoration:none}
header p{margin:1px 0 0;font-size:12.5px;opacity:.82;color:#fff}
nav{
  background:var(--card);border-bottom:1px solid var(--border);
  position:sticky;top:0;z-index:20;
}
.nav-inner{
  max-width:1080px;margin:0 auto;display:flex;gap:2px;padding:0 24px;
  overflow-x:auto;scrollbar-width:none;
}
.nav-inner::-webkit-scrollbar{display:none}
.nav-inner a{
  padding:12px 14px;font-size:14px;color:var(--muted);white-space:nowrap;
  border-bottom:2px solid transparent;
}
.nav-inner a:hover{color:var(--primary);text-decoration:none}
.nav-inner a.active{color:var(--primary);border-bottom-color:var(--primary);font-weight:600}
main{max-width:1080px;margin:0 auto;padding:26px 24px 40px}
h2.page-title{font-size:26px;margin:0 0 6px}
.lead{color:var(--muted);font-size:15px;margin:0 0 22px;max-width:760px}
.card{
  background:var(--card);border:1px solid var(--border);border-radius:var(--radius);
  padding:18px;margin-bottom:16px;
}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media(max-width:760px){.grid{grid-template-columns:1fr}}
label{display:block;font-size:13px;color:var(--muted);margin-bottom:6px}
textarea,input[type=text],select{
  width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:8px;
  font-size:14px;font-family:inherit;background:#fff;color:var(--text);outline:none;
}
textarea{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;min-height:150px;resize:vertical}
textarea:focus,input[type=text]:focus,select:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(37,99,235,.1)}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:12px}
button.btn{
  background:var(--primary);color:#fff;border:0;padding:10px 20px;border-radius:8px;
  cursor:pointer;font-size:14px;font-weight:500;text-decoration:none;display:inline-block;
}
button.btn:hover{background:#1d4ed8;text-decoration:none}
button.btn:disabled{opacity:.6;cursor:not-allowed}
button.ghost,.ghost-link{
  background:#fff;color:var(--text);border:1px solid var(--border);padding:8px 14px;
  border-radius:8px;cursor:pointer;font-size:13px;text-decoration:none;display:inline-block;
}
button.ghost:hover,.ghost-link:hover{border-color:var(--primary);color:var(--primary);text-decoration:none}
.chips{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}
.chip{
  display:inline-flex;align-items:center;gap:6px;font-size:13px;color:var(--muted);
  background:#f9fafb;border:1px solid var(--border);border-radius:20px;padding:4px 12px;cursor:pointer;
}
.chip input{accent-color:var(--primary)}
pre{
  background:#0f172a;color:#e2e8f0;padding:14px;border-radius:10px;overflow:auto;
  font-size:13px;line-height:1.55;margin:0;max-height:460px;
  font-family:ui-monospace,SFMono-Regular,Menlo,monospace;white-space:pre-wrap;word-break:break-all;
}
.status{font-size:13px;margin-top:10px;min-height:20px;color:var(--muted)}
.status.ok{color:var(--ok)}
.status.err{color:var(--err)}
.hint{font-size:12px;color:var(--muted);margin-top:6px}
table{width:100%;border-collapse:collapse;font-size:14px}
th,td{text-align:left;padding:8px 10px;border-bottom:1px solid var(--border)}
th{color:var(--muted);font-weight:500;font-size:13px}
.svg-box{background:#fff;border:1px solid var(--border);border-radius:10px;padding:12px;display:grid;place-items:center;min-height:200px}
.svg-box svg{max-width:100%;height:auto}
.badge{display:inline-block;background:var(--primary-soft);color:var(--primary);border-radius:6px;padding:2px 8px;font-size:12px;font-weight:600}
.metric{font-size:28px;font-weight:700;color:var(--primary)}
.viewer{border:1px solid var(--border);border-radius:10px;overflow:hidden;background:#fff;position:relative}
footer{text-align:center;color:var(--muted);font-size:12px;padding:26px;border-top:1px solid var(--border);margin-top:20px}
footer a{color:var(--muted)}
/* landing */
.hero{padding:8px 0 22px}
.hero h2{font-size:32px;margin:0 0 10px;line-height:1.25}
.hero p{color:var(--muted);font-size:16px;max-width:720px;margin:0}
.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px;margin:24px 0}
.tool-card{
  background:var(--card);border:1px solid var(--border);border-radius:var(--radius);
  padding:20px;display:block;color:inherit;transition:.15s;
}
.tool-card:hover{border-color:var(--primary);box-shadow:0 4px 16px rgba(37,99,235,.08);text-decoration:none;transform:translateY(-1px)}
.tool-card h3{margin:0 0 6px;font-size:16px;color:var(--text)}
.tool-card p{margin:0;font-size:13.5px;color:var(--muted)}
.tool-icon{font-size:22px;margin-bottom:10px}
.prose{max-width:800px}
.prose h2{font-size:19px;margin:28px 0 8px}
.prose h3{font-size:15.5px;margin:18px 0 6px}
.prose p,.prose li{font-size:14.5px;color:#374151}
.prose ul{padding-left:22px}