HTML：
<div class="box">
<div class="content">
<div>内容1</div>
<div>内容2</div>
</div>
</div>
CSS：
.box {
width: 200px;
background: blue;
position: relative;
height: 200px
}
.content {
padding: 5px 10px;
color: white;
width: fit-content;
height: fit-content;
position: absolute;
top: 0;
bottom: 0;
left: 0;
right: 0;
background: red;
margin: auto;
}效果：
