JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container-fluid">

    <div class="row row1">

        <br>

    </div>

    <div class="row row2">

        <br>

    </div>

</div>

CSS

* {
  margin: 0;
}

.row1{
    background-color: orange;
}

.row2{
    background-color: blue;
}
.container-fluid {
  display: flex;
  flex-direction: column;
  height: 100%;
}
.row:last-child {
  flex: 1;
}