1'em' units for the font-size property will be relative to the'font-size of the parent element'.
2'em' units on other properties other than font-size will be relative to the
3font-size of the current element. 'rem' units sizes will always be relative
4to the font-size of the root html element.
1em -> Relative to the font-size of the element
2(2em means 2 times the size of the current font)