求各位大神帮忙解决一下!!!为什么下面的代码就是不能居中?
*{ margin:0; padding:0; }
.wrapper {
position: relative;
width: 500px;
height: 500px;
background-color: #ddd;
}
.content{
background-color:#6699FF;
width:200px;
height:200px;
position: absolute;
top: 50%;
left: 50%;
margin-top:-100px ;
margin-left: -100px;
}
</style>
<body>
<div class="wrapper">
<div class="content"></div>
</div>
</body>