Check out example codes for "css 100% height". It will help you in understanding the concepts better.

Code Example 1

.left {
  height: 100vh;
  width: 50%;
  background-color: grey;
  float: left;
}

.right {
  height: 100vh;
  width: 50%;
  background-color: red;
  float: right;
}

Code Example 2

<!DOCTYPE html>
<html>
  <head>
    <title>100% height</title>
    <style>
      html,
      body {
        height: 100%;
        margin: 0;
      }
      .container {
        height: 100%;
        background: #000; /* to see the effect */
      }
    </style>
  </head>
  <body>
    <div class="container"></div>
  </body>
</html>

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