Problem: In several interfaces, our UI "jumps" after JavaScript has been loaded and "enhanced" the page.

Context: Many functions on Mediawiki need to be accessible with and without Javascript. Typically there is a plain HTML/CSS version and JavaScript is added to do a "progressive enhancement" of the existing html/css.

Solution: We hope there is a solution or established practice to avoid the jumps.

Reading:
Progressive Enhancement: https://alistapart.com/article/understandingprogressiveenhancement
A similar CSS problem: https://en.wikipedia.org/wiki/Flash_of_unstyled_content