css 自适应居中写法
//自适居中内容
.popup {
position: fixed;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
background: #fff;
padding: 20px;
border-radius: 10px;
z-index: 998;
width: 80%;
}
//背景
.mask {
position: fixed;
top: 0;
left: 0;
right: 0;
bottom: 0;
background: rgba(0, 0, 0, 0.5);
z-index: 998;
}