<div class="box box1">
        <span>垂直居中</span>
</div>

.box1{
    display: table-cell;
    vertical-align: middle;
    text-align: center;        
}

.box2{
    display: flex;
    justify-content:center;
    align-items:Center;
}

.box3{position:relative;}
.box3 span{
            position: absolute;
            width:100px;
            height: 50px;
            top:50%;
            left:50%;
            margin-left:-50px;
            margin-top:-25px;
            text-align: center;
        }

.box4 span{
  width: 50%; 
  height: 50%; 
  background: #000;
  overflow: auto; 
  margin: auto; 
  position: absolute; 
  top: 0; left: 0; bottom: 0; right: 0; 
}

.box6 span{
            position: absolute;
            top:50%;
            left:50%;
            width:100%;
            transform:translate(-50%,-50%);
            text-align: center;
        }

.box7{
  text-align:center;
  font-size:0;
}
.box7 span{
  vertical-align:middle;
  display:inline-block;
  font-size:16px;
}
.box7:after{
  content:'';
  width:0;
  height:100%;
  display:inline-block;
  vertical-align:middle;
}

.box8{
    display: flex;
    text-align: center;
}
.box8 span{margin: auto;}

.box9{
    display: -webkit-box;
    -webkit-box-pack:center;
    -webkit-box-align:center;
    -webkit-box-orient: vertical;
    text-align: center
}

<div class="floater"></div>  
<div class="content"> Content here </div>  

.floater {
    float:left; 
    height:50%; 
    margin-bottom:-120px;
}
.content {
    clear:both; 
    height:240px; 
    position:relative;
}