*{box-sizing:border-box}body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;margin:0;color:#1f2937;background:#f8fafc;line-height:1.55}
header,main,footer{max-width:960px;margin:0 auto;padding:16px}header h1{margin:0;font-size:26px}header p{color:#475569;margin:6px 0 0}nav a{margin-right:12px}a{color:#2563eb}
.small{font-size:13px;color:#64748b}.card{background:#fff;border:1px solid #e2e8f0;border-radius:10px;padding:16px 20px;margin:12px 0}
input{font:16px ui-monospace,Menlo,Consolas,monospace;padding:10px;width:100%;max-width:520px;border:1px solid #cbd5e1;border-radius:8px}button{font-size:15px;padding:9px 16px;border-radius:8px;border:1px solid #2563eb;background:#2563eb;color:#fff;cursor:pointer}
table{border-collapse:collapse;font-size:14px}td,th{border:1px solid #e2e8f0;padding:5px 8px;text-align:left;vertical-align:top}th{background:#f8fafc}
.ok{color:#166534;font-weight:600}.bad{color:#b91c1c;font-weight:600}.cols{columns:3 220px;font-size:14px}code{background:#f1f5f9;padding:1px 4px;border-radius:4px}
footer{font-size:13px;color:#64748b;border-top:1px solid #e2e8f0;margin-top:24px}