<div class="container">
  <div class="left"></div>
  <div class="mid"></div>
  <div class="right"></div>
</div>
html,body {height: 100%;}
.container {display: flex; min-width: 200px; height: 100%;}
.left {width: 80px; height: 200px; background-color: #4688f5;}
.mid {flex: 1; height: 100%; background-color: yellow;}
.right {width: 120px; height: 100px; background-color: tomato;}

External CSS

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External JavaScript

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