Resizing an element in 100px intervals with round(). Currently (2023) only works in Firefox & Safari (using % in Safari doesn't work, but vw works). This + flex would be awesome to have.
Resizing an element in 100px intervals with CSS grid grid-template-columns:repeat(auto-fit,100px);. Not sure how flexible, but so far the best method. Needs a nested element.
Resizing an element in 100px intervals with multiple CSS media queries and CSS variables. Scrollbar messes up calculations..! Lots of media queries also... not too bad with CSS variables but still.