body { font-family: Arial, sans-serif; margin: 20px; }
header nav { background: #333; padding: 10px; }
header nav a { color: #fff; margin-right: 10px; text-decoration: none; }
header nav a:hover { text-decoration: underline; }
main { padding: 20px; }
table { border-collapse: collapse; width: 100%; }
th, td { border: 1px solid #ccc; padding: 8px; text-align: left; }
th { background: #f5f5f5; }
input[type=text], input[type=password], input[type=number], input[type=date], select, textarea {
    padding: 6px; margin: 4px 0; border: 1px solid #ccc; border-radius: 3px;
}
input[type=submit], button { padding: 8px 16px; background: #333; color: #fff; border: none; cursor: pointer; border-radius: 3px; }
input[type=submit]:hover, button:hover { background: #555; }
.error { color: red; }
.success { color: green; }
.form-group { margin-bottom: 12px; }
label { display: inline-block; min-width: 200px; font-weight: bold; }