I discovered this CSS oddity while trying to figure out why my plan to use (negative) margins to create a new "effective" content box wasn't working with percen

I discovered this CSS oddity while trying to figure out why my plan to use (negative) margins to create a new "effective" content box wasn't working with percent units (but worked with other units). The best explanation seems to be in the middle of this article: https://www.aleksandrhovhannisyan.com/blog/css-aspect-ratio/#why-it-works-percentage-padding-and-css-aspect-ratios https://www.aleksandrhovhannisyan.com/blog/css-aspect-ratio/...