I’ve created the following diagram of how i would like my UI to look:

but i just can’t get it to behave the way I want to using css.
I’ve tried to build it with CSS Grids, but instead of overflowing it’s expanding beyond the max-width.
How would I do i contrain the app to 100vh or what other approaches would work?
>Solution :
CSS-Grid is what you want here. Just specify the grid-container height as 100vh
* {
margin: 0;
padding: 0;
min-width: 0;
min-height: 0;
box-sizing: border-box;
}
::before,
::after {
box-sizing: inherit;
}
.grid {
display: grid;
grid-template-columns: repeat(2, 1fr);
grid-auto-rows: auto auto 1fr 1fr;
height: 100vh;
text-align: center;
gap: .25em;
}
.nav {
grid-column: 1 / span 2;
background: lightblue;
padding: 1em;
}
main {
grid-row: 2 / span 3;
background: green;
}
.controls {
background: lightgrey;
padding: .5em;
}
.scroll {
overflow: auto;
border: 1px solid green;
}
.h {
height: 500px;
background: linear-gradient(red, blue);
}
<div class="grid">
<div class="nav">Navbar</div>
<main>Main</main>
<div class="controls">Controls</div>
<div class="scroll">
<div class="h"></div>
</div>
<div class="scroll">
<div class="h"></div>
</div>
</div>