css height always full screen code example

Example 1: make a div full screen css

height: 100vh

Example 2: css set div heigtto screen

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

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