Page Inspector
Use the Page Inspector to examine and modify the HTML and CSS of a page.
You can examine pages loaded in the local copy of Firefox or in a remote target such as Firefox for Android. Seeabout debugging to learn how to connect the developer tools to a remote target.
User Interface Tour
To find your way around the Inspector, here’s aquick tour of the UI.
You can split the Rules view out into its own pane, separate from the other tabs on the CSS pane — this is called3-pane mode.
How to
To find out what you can do with the Inspector, see the following how to guides: