*{box-sizing:border-box}body{margin:0;font-family:Arial,sans-serif;background:#f6f8fc;color:#111827}
header{background:#0f172a;color:#fff;padding:22px 16px}.wrap,main{max-width:1120px;margin:auto}
.brand{font-size:23px;font-weight:800}.tag{color:#cbd5e1;margin-top:5px}
main{padding:25px 16px}.nav{display:flex;gap:14px;flex-wrap:wrap;margin-bottom:20px}.nav a{color:#2563eb;text-decoration:none}
.card,.tool{background:#fff;border:1px solid #e5e7eb;border-radius:16px;padding:22px;box-shadow:0 8px 30px #0f172a0d;margin-bottom:18px}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.tool a{color:#2563eb;text-decoration:none;font-weight:700}
.tool p{color:#64748b;line-height:1.6}h1{font-size:34px}textarea,input,select{width:100%;padding:12px;border:1px solid #cbd5e1;border-radius:9px;margin:6px 0 13px;font:inherit}textarea{min-height:190px}
button{padding:11px 16px;border:0;border-radius:9px;background:#2563eb;color:#fff;font-weight:700;cursor:pointer;margin:3px}.secondary{background:#475569}
.output{white-space:pre-wrap;background:#f1f5f9;padding:14px;border-radius:10px;margin-top:12px;min-height:55px;overflow:auto}
iframe{width:100%;height:330px;border:1px solid #cbd5e1;border-radius:10px;background:#fff;margin-top:12px}
footer{text-align:center;padding:32px;color:#64748b}@media(max-width:850px){.grid{grid-template-columns:repeat(2,1fr)}}@media(max-width:600px){.grid{grid-template-columns:1fr}h1{font-size:28px}}