<div class="login-container">
     //这个div就是背景图
     <div class="beijing"></div>
     //这个div就是显示的内容块，也就是我的logo和登录框
     <div class="content"></div>
  </div>

 .login-container{
    position: relative;
    width: 100%;
    height:100%;
    position: relative;
    //利用flex布局让内容content模块垂直居中
    display: flex;
    flex-direction: column;
    position: relative; 
  }
 .beijing{  //背景图样式
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0px;
    top:0px;
    background: url('../../../static/img/timg (1).jpg');
    background-repeat: no-repeat;
    background-size: cover;
    -webkit-filter: blur(10px);
    -moz-filter: blur(10px);
    -o-filter: blur(10px);
    -ms-filter: blur(10px);
    filter: blur(10px);
  }
.content{  //内容图样式
	width: 80%;
	height: 70%;
	position: absolute;
	z-index: 5;
}