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CSS CSS Basics (2014) Fundamental Concepts The Cascade: Specificity and Source Order

Fábio Tavares da Costa
Fábio Tavares da Costa
11,985 Points

How to Access the User Agent Style Sheet?


I hear developers talk about styles applied by User Agents. How can we access these rules?


3 Answers

Christopher Vesti
Christopher Vesti
1,622 Points

User Agent Style sheets simply refer to the default styles that browsers apply to web pages. It is of the lowest importance considering User Styles and Author styles will overwrite these. Each browser is a little different in how it displays "unstyled" html.

If you want to see first hand how browsers display html, create a simple .html document with different header, paragraph and image elements and open it with different browsers.

Fábio Tavares da Costa
Fábio Tavares da Costa
11,985 Points


Firefox has an option we can toggle on/off to show browser styles.

In Chrome I see user agent stylesheet in the upper right corner. That's the stylesheet I am looking for.

Plain html will show fragments of computed styles like:

p {
  display: block;
  -webkit-margin-before: 1em;
  -webkit-margin-after: 1em;
  -webkit-margin-start: 0px;
  -webkit-margin-end: 0px;

Where is the complete list of rules?

Hi Fábio Tavares da Costa, you can find the full list of all styles in each User Agent Stylesheet in the following locations:

Fábio Tavares da Costa
Fábio Tavares da Costa
11,985 Points

I will do this,

Still, the style sheet itself should be accessible client side. Maybe a plain html file will make the browse reveal it's CSS URI.