"I decided to invest in a real life race horse because why not"
Haha that's so relatable. When I played Game Dev Tycoon I bought a game studio on a whim. Just normal people stuff, right?
height: calc(100vh - _px) on the root container and display: flex; flex-direction: column; height: 100% on the columns. The panel size can be controlled with flex and no hardcoded fixed heights.height: calc(100vh - _px) on the root container and display: flex; flex-direction: column; height: 100% for the columns. The panel size is completely automatic thanks to flexbox.calc(___vh - ___px) in there, too. height : 100% and arbitrary hardcoded values for height, min-height and max-height.