*{box-sizing:border-box}
body{margin:0;font-family:Arial,sans-serif;background:#f4f6f8;color:#1f2937}
.header{background:#0f172a;color:#fff;padding:26px;text-align:center}
.header .sub{opacity:.9;margin:8px 0 0}
.contenedor{max-width:900px;margin:24px auto;padding:0 16px}
.card{background:#fff;padding:20px;border-radius:12px;box-shadow:0 8px 20px rgba(0,0,0,.08)}
label{display:block;margin-top:12px;font-weight:bold}
input,textarea{width:100%;padding:10px;border:1px solid #cbd5e1;border-radius:10px;margin-top:6px}
.btn{margin-top:14px;padding:12px 16px;border:0;border-radius:10px;background:#2563eb;color:#fff;cursor:pointer}
.btn:hover{background:#1d4ed8}
.btn-link{color:#2563eb;text-decoration:none}
.btn-link.light{color:#fff;text-decoration:underline}
.footer{text-align:center;padding:20px;color:#64748b}