body {
            background-color: #007bff;
            font-family: Arial, sans-serif;
            display: flex;
            justify-content: center;
            align-items: flex-start;
            padding-top: 10px;
            height: 100vh;
            margin: 0;
        }
        .container {
            background-color: white;
            padding: 30px;
            border-radius: 10px;
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
            max-width: 1000px;
            width: 100%;
            text-align: center;
        }
        h1 {
            color: black;
            text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
            font-style: italic;
            font-weight: bold;
        }
        .btn-classic {
            background-color: #007bff;
            color: white;
            border: none;
            padding: 10px 20px;
            font-size: 16px;
            border-radius: 5px;
            cursor: pointer;
            transition: background-color 0.3s;
            margin-top: 20px;
            display: inline-flex;
            align-items: center;
        }
        .btn-classic i {
            margin-right: 5px;
        }
        .btn-classic:hover {
            background-color: #0056b3;
        }
        .btn-danger {
            background-color: #dc3545;
        }
        .btn-danger:hover {
            background-color: #c82333;
        }
        .form-control {
            margin-bottom: 20px;
        }
        .form-inline {
            display: flex;
            justify-content: space-between;
        }
        .card-container {
            display: flex;
            justify-content: space-around;
            margin-top: 20px;
        }
        .card-preview {
            position: relative;
            width: 100%;
            max-width: 400px;
            height: 200px;
            background: url('https://via.placeholder.com/400x200') no-repeat center/cover;
            border-radius: 10px;
            color: white;
            text-align: left;
            padding: 20px;
            margin-bottom: 20px;
        }
        .card-number, .card-expiry, .card-cvv {
            margin-top: 20px;
        }
        .card-back {
            background: url('https://via.placeholder.com/400x200?text=Verso') no-repeat center/cover;
        }
        .form-group input[type="text"] {
            max-width: 100%;
            padding-right: 40px;
            -webkit-appearance: none;
            -moz-appearance: none;
        }
        @media only screen and (max-width: 768px) {
            .form-inline {
                flex-direction: column;
            }
            .card-container {
                flex-direction: column;
                align-items: center;
            }
        }