.gradient-bg {
        margin-left: auto;
        margin-right: auto;
            background: #2c3e50;
            border: 4px solid #3f8fef;
        padding: 30px;
        border-radius: 12px;
        box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        width: 100%;
        max-width: 800px;
        text-align: center;
        }
        .preview-transition {
            transition: width 0.3s ease-in-out;
        }