如何修改此HTML JS页面加载脚本以淡出白色背景和图标

<style>
    @keyframes fade-out {
        from { opacity: 1; }
        to { opacity: 0; }
    }
</style>

<script>
    document.addEventListener("DOMContentLoaded", function() {
        // 在此处添加淡出效果的代码
    });
</script>

<script>
    document.addEventListener("DOMContentLoaded", function() {
        var background = document.querySelector(".background");
        var icon = document.querySelector(".icon");

        background.classList.add("fade-out");
        icon.classList.add("fade-out");
    });
</script>

<style>
    .fade-out {
        animation: fade-out-animation 1s ease-out;
    }

    @keyframes fade-out-animation {
        from { opacity: 1; }
        to { opacity: 0; }
    }
</style>