body {
            background: #f0f4f8;
            font-family: Arial, sans-serif;
            margin: 0;
        }
        .navbar {
            background: #23a7fa;
            padding: 15px 30px;
            border-radius: 8px;
            margin: 16px 0;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }
        .navbar .brand {
            color: #fff;
            font-weight: bold;
            font-size: 1.2em;
            margin-right: 20px;
        }
        .navbar nav a {
            color: #fff;
            text-decoration: none;
            margin: 0 12px;
            font-weight: 500;
        }
        .container {
            background: #fff;
            width: 360px;
            margin: 40px auto;
            border-radius: 8px;
            padding: 28px;
            box-shadow: 0 2px 8px rgba(34, 34, 34, 0.09);
        }
        h2 {
            color: #23a7fa;
            text-align: center;
        }
        form {
            margin-top: 16px;
        }
        label {
            display: block;
            margin: 10px 0 4px 0;
            color: #444;
        }
        input[type="text"], input[type="number"], input[type="email"] {
            width: 96%;
            padding: 8px;
            margin-bottom: 14px;
            border-radius: 4px;
            border: 1px solid #ddd;
            font-size: 1em;
        }
        .pay-btn {
            background: #23a7fa;
            color: #fff;
            padding: 12px;
            width: 100%;
            border: none;
            border-radius: 4px;
            font-size: 1em;
            cursor: pointer;
            margin-top: 8px;
        }
        .details {
            background: #eaf6ff;
            padding: 12px;
            border-radius: 6px;
            margin-top: 26px;
        }