When setting widths and heights in CSS, are “vw” and “vh” compatible with every browser and with any device? Which bad practices should be avoided in regard?

Answer 1

Here is a chart that shows which CSS codes are supported in which browsers: https://www.w3schools.com/cssref/css3_browsersupport.asp

My preference when it comes to setting sizes in CSS are em for elements that need to be flexible and px for those which do not. Images that I know I don't want to change sizes when they are on a smaller device, I use pixels as my units. If it is an element I want to shift as they site is shown on mobile devices, I use percentages or em units. Always remember to consider how your web project looks on small screens.