SOURCE

<div class="mian">
  <div class="left">left</div>
  <div class="center">center</div>
  <div class="right">right</div>
</div>

body { margin: 0 }
.main { width: 100%, height: 500px; position: relative; }

.left,.right,.center { position: absolute; }

.left {
  left: 0;
  width: 200px;
  height: 500px;
  background-color: lightblue;
}
.right {
  right: 0;
  width: 200px;
  height: 500px;
  background-color: lightblue;
}

.center {
  left: 200px;
  right: 200px;
  background-color: pink;
  height: 500px;
}