效果如图：当浏览器滚轮在最上面的时候 没什么区别。当鼠标滚轮超出最上面高度时会有这种粒子感。吸顶遮盖下面内容

首先要 明确 css 基础属性 position: sticky;的用法。再了解
background-image: radial-gradient(transparent 1px, #fff 1px);
background-size: 4px 4px;
backdrop-filter: saturate(50%) blur(4px);

vue 代码：

<template><div style="height: 500px; overflow: auto"><div class="top-div"><div>xx<el-button type="info" size="mini">htllo</el-button>xx</div></div><div><div v-for="item in indexArr" :key="item" style="margin-bottom: 5px">{{ item }}+j ioash haugh adhgajd faihdg ioahgaf nFN OIHG OIAHG IOAJSIO JO<el-button type="primary">xxasd sud</el-button><el-tag type="warning">xxhasdhiuash </el-tag></div></div></div>
</template><script>
export default {data() {return {indexArr: [],};},mounted() {setTimeout(() => {for (let i = 1; i <= 100; i++) {this.indexArr.push(i);}}, 1000);},methods: {},
};
</script><style lang='scss'>
.top-div {position: sticky;top: 0;left: 0;height: 55px;border-bottom: 1px solid #ccc;background-image: radial-gradient(transparent 1px, #fff 1px);background-size: 4px 4px;backdrop-filter: saturate(50%) blur(4px);
}
</style>