body { font-family: Arial, sans-serif; margin: 20px; }
.navbar { background: #333; padding: 15px; }
.navbar a { color: white; margin: 0 15px; text-decoration: none; }
.card { border: 1px solid #ddd; padding: 15px; margin: 10px; width: 300px; display: inline-block; }
.alert { padding: 10px; background: #d4edda; border: 1px solid #c3e6cb; margin: 10px 0; }
table { width: 100%; border-collapse: collapse; }
th, td { border: 1px solid #ddd; padding: 8px; text-align: left; }
.btn {
    padding: 8px 12px;
    text-decoration: none;
    border-radius: 4px;
    display: inline-block;
    margin: 5px 0;
}
.btn-primary { background: #007bff; color: white; }
.btn-success { background: #28a745; color: white; }
.btn-danger { background: #dc3545; color: white; }
.btn-warning { background: #ffc107; color: black; }