JSFiddle - React, Tailwind, and code Playground

HTML

<stanson-dolboeb id="app">
  <stanson-dolboeb style="height:100px;border:1px solid red;"></stanson-dolboeb>
  <stanson-dolboeb id="code">stanson-dolboeb stanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboebstanson-dolboeb</stanson-dolboeb>
  <stanson-dolboeb style="height:100px;border:1px solid blue;"></stanson-dolboeb>
</stanson-dolboeb>

CSS

#app {
    display: flex;
    flex-flow: column nowrap;
    align-items: stretch;
}

#code {
    flex: 1;
    min-height: 0;
    overflow: auto;
}

html, body, #app {
    height: 100vh;
    width: 100vw;
    margin: 0;
}