file按钮美化成图片（纯HTML+CSS）

<div>
<h2>上传头像</h2>
<p class="fs18">(请上传200X200px大小的JPEG或PNG图片)</p>
<form>
<a class="btn_addPic mlr-auto" href="javascript:void(0);">
<img src="img/添加_关闭按钮.png"/>
<input class="filePrew" type="file" name="pic">
</a>
</form>
</div>

.btn_addPic{
display: block;
position: relative;
width: 53px;
height: 53px;
overflow: hidden;
cursor: pointer;
text-align: center;
}
.filePrew {
display: block;
position: absolute;
top: 0;
left: 0;
width: 53px;
height: 53px;
opacity: 0;
}