SOURCE

<div id="wrapper">
  <div class="box1">box1</div>
  <div class="box2">box2</div>
  <div class="box3">box3</div>
  <div class="box4">box4</div>
</div>

#wrapper div{
  background-color:lightpink;
  border:1px solid black;
  width:25%;
  text-align:center;
  display:inline-block;
  font-size:12px;
  box-sizing:border-box;//将border宽度划到width，width=content+padding+border
}
#wrapper{
  font-size:0
}