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CSS CSS Basics (2014) Understanding Values and Units Rem Units

Routine Poutine
Routine Poutine
26,050 Points
Posted by Routine Poutine
Routine Poutine
26,050 Points

If REM is root and EM is parent, is the root a constant and a parent relative -- is the root always 16px?

Hi, a little confused here. Is the root element fixed or customized? Thanks, Matt

1 Answer

Steven Parker
Steven Parker
229,708 Points
Steven Parker
Steven Parker
229,708 Points

REM has a default size based on the browser, though it's nearly always the same. But it's not a constant, you can always change it in CSS or JavaScript code. Think of it as a "document-wide variable".

You might enjoy this blog post with facts and uses for REM. It's called There’s more to the CSS rem unit than font sizing.