How does rem differ from em in CSS?
css
Solution
`EM`s are relative to their parent's font size
`REM`s are relative to a base font-size
This is important when intermediate containers change font sizes. Child elements with EMs will be affected, those using REMs will not.
Problem
In website source, I have sometimes seen developers use the `rem` unit. Is it similar to `em`? I tried it to see what it actually does, but what is it relative to? Demo HTML ``` <div>Hello <p>World</p></div> ``` CSS ``` div { font-size: 1.4rem; } div p { font-size: 1.4rem; } ```