How do I apply css to firefox extension elements?

I want to style 开发者_高级运维different elements of my firefox extension. This is how I include css:

<?xml-stylesheet href="chrome://global/skin/sidebar.css" type"text/css" ?>

E.g. I want to change the color of the

<tab label="Start"/>

elements.

I set

tab{
 color:red;
}

but it is not working. Any idea how to achieve that?

You have to reference the CSS file of your extension... I don't think your extension's name is global.

Should be something along the lines of chrome://yourextensionsname/skin/sidebar.css