*{box-sizing:border-box}body{margin:0;font:16px/1.6 system-ui,sans-serif;color:#1f2937;background:#f3f4f6}
header{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:8px;padding:12px 20px;background:#fff;border-bottom:1px solid #e5e7eb}
.brand{font-weight:700;font-size:20px;color:#2563eb;text-decoration:none}
nav a{margin-left:16px;color:#374151;text-decoration:none}nav a:hover{color:#2563eb}
main{max-width:720px;margin:24px auto;padding:24px;background:#fff;border-radius:8px;box-shadow:0 1px 3px rgba(0,0,0,.08)}
h1{margin-top:0}label{display:block;margin:14px 0 4px;font-weight:600}
input[type=text],input[type=password],input[type=email],textarea{width:100%;padding:10px;border:1px solid #d1d5db;border-radius:6px;font:inherit}
button,.btn{display:inline-block;margin-top:16px;padding:10px 20px;border:0;border-radius:6px;background:#2563eb;color:#fff;font:inherit;cursor:pointer;text-decoration:none}
button.danger{background:#dc2626}.alert{padding:12px;border-radius:6px;margin:12px 0}
.err{background:#fee2e2;color:#991b1b}.ok{background:#dcfce7;color:#166534}.warn{background:#fef3c7;color:#92400e}
.chk label{font-weight:400;display:flex;gap:8px;align-items:flex-start}footer{text-align:center;color:#6b7280;padding:16px;font-size:14px}