如何做H5页面阴影悬浮效果

<div class="list">
<div class="list-close"></div>
<section>
<p class="list-all-btn">xxx</p>
<div class="list-wrap"></div>
<p class="cancel-btn" data-reactid=".0.1.1.1.2">取消</p>
</section>
</div>

.list {
position: absolute;
top: 0;
left: 0;
z-index: 9;
background: rgba(0,0,0,0.4);
width: 100%;
height: 100%;
}

list-close {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}

.list > section {
position: absolute;
bottom: 0;
left: 0;
width: 100%;
background: #f8f8f8;
}

.list-all-btn {
text-align: center;
color: #808080;
font-size: 12px;
height: 44px;
line-height: 44px;
border-bottom: 1px solid #e3e2e7;
}

.cancel-btn {
font-size: 20px;
line-height: 45px;
border-top: 1px solid #e3e2e7;
color: #000;
text-align: center;
margin-top: 20px;
background: #fff;
}