在页面中重叠两个单独的div

<style>
    .div1 {
        position: absolute;
        top: 100px;
        left: 100px;
        width: 200px;
        height: 200px;
        background-color: red;
        z-index: 2;
    }
    
    .div2 {
        position: absolute;
        top: 150px;
        left: 150px;
        width: 200px;
        height: 200px;
        background-color: blue;
        z-index: 1;
    }
</style>

<div class="div1"></div>
<div class="div2"></div>