CSS: 100% font size - 100% of what?

Question

There are many articles and questions about percentage-sized vs other-sized fonts. However, I can not find out WHAT the reference of the percent-value is supposed to be. I u

Answer 1

My understanding is that when the font is set as follows

body {
  font-size: 100%;
}

the browser will render the font as per the user settings for that browser.

The spec says that % is rendered

relative to parent element's font size

http://www.w3.org/TR/CSS1/#font-size

In this case, I take that to mean what the browser is set to.