PUBLIC MARKS from decembre with tags xul & user

When editing userChrome.css, you must add CSS selectors based on the element names and IDs/classes of the XUL user interface. There is no comprehensive listing of every single possible selector to use when styling the user interface (just as it would be silly to create such a comprehensive list for a web page), but a few of the more common and interesting selectors are listed below. The best way to discover how to select an element in the user interface is to use the DOM Inspector.

You can inspect the Firefox user interface directly with DOM Inspector. (Which is not the same Inspector as in the Web Developer menu.) [addons.mozilla.org] https://addons.mozilla.org/en-US/firefox/addon/dom-inspector-6622/Click the icon in the upper-left corner of DOMi, the one with a pointer on it, then click anywhere in the browser to select an element; that element will be highlighted in the left column. Right-click the highlighted entry to display a context menu: "Copy Selector" suggests selectors for the element, "Set Pseudo-classes..." lets you switch on :hover. Notice that the browser itself is a document with its own URI, chrome://browser/content/browser.xul, Most of the browser chrome is XUL, but some, such as the Stylish editor, is HTML embedded in XUL. https://developer.mozilla.org/en-US/docs/XUL