people always ask me this like they heard its a concern or something. To me it seems pretty intuitive. each widget can ask how much available space it has and can render inside that or less without any knowledge of its container. Containers set the available space.

In my timelines I use a strip layout, just 1/n of the screen with a minimum size and a horizontal scrollbar if it doesn’t fit.

Then I just render notes inside those strips. I like that each thing on the UI is a self contained struct or function, everything composes together very nicely just by immediate-mode render commands. Its 1000x less bs than the dom and virtual dom nonsense.