SOURCE

  <div class="body">
    <div class="header"></div>
    <div class="main">
      <div class="left"></div>
      <div class="center"></div>
      <div class="right"></div>
    </div>
  </div>

html, body{
    height: 100%;
    widows: 100%;
    padding: 0;
    margin: 0;
}
.body{
    display: flex;
    height: 100%;
    flex-direction: column;
    background-color: red;
}
.header{
    height: 80px;
    background-color: blueviolet
}
.main{
    flex: 1;
    background-color: white;
    display: flex;
}
.left{
    width: 100px;
    height:300px;
    background-color: #eccc68;
}
.center{
    width: 200px;
    height: 1000px;
    background-color: #7bed9f;
}
.right{
    width: 100px;
    height: 400px;
    background-color:#eccc68;
}