基于 vertical-align 属性的水平垂直居中弹框

  
  
  



  
abc

* {
  margin: 0;
  padding: 0;
}
body {
  background-color: yellow;
}
.container {
  position: fixed;
  top:0; right:0; bottom:0; left:0;
  background-color: rgba(0,0,0,0.3);
  text-align: center;
  font-size: 0;
  white-space: nowrap;
  overflow: auto;
}

.container:after {
  content: '';
  display: inline-block;
  height: 100%;
  vertical-align: middle;
}

.dialog {
  display: inline-block;
  vertical-align: middle;
  text-align: left;
  font-size: 14px;
  white-space:normal;
  border: 1px solid;
}