<div class="wrapper">
<div class="content"></div>
</div>
.wrapper{
position: relative;
width: 100px;
height: 100px;
background-color: red;
}
.content{
position: absolute;
left: 50%;
top: 50%;
width: 10px;
height: 10px;
background-color: green;
}
不算。退一万步讲你忘了计算content 的 width和height了。不建议这样子居中