Use rem units for sizing that doesn't need em units, and that should scale de...

Use rem units for sizing that doesn't need em units, and that should scale depending on browser font size settings. Use rem units unless you're sure you need em units, including on font sizes. Use rem units on media queries. Don't use em or rem in multi-column layout widths - use % instead.

Found an article for this: https://webdesign.tutsplus.com/tutorials/comprehensive-guide-when-to-use...