记录代码，我就不截图了

<style>
    .top
    {
        backdrop-filter:blur(10px);
        -webkit-backdrop-filter:blur(10px);
        background-color: rgba(242,242,242,0.5);
        height: 56px;
        width: 100%;
        box-sizing: border-box;
        position: fixed;
        left: 0px;
        top: 0px;
    }
</style>
<div class="top" align="center"></div>