Joshua Kohantab4,247 Points
Why does the instructor, using fixed padding values for the main nav elements and not em units
I've trouble with understanding when to use em and when to use fixed units when it comes to padding and margin
Steven Parker203,989 Points
You use em units when you want something to vary proportionally to the font size, and px units when you want something to always have the same size. It's often a design choice, so it can depend on what look you're trying to achieve as to which you use.