This extension inserts the Pesticide CSS into the current page, outlining each element to better see placement on the page.
In this version the banner at the bottom is off by default. To turn it on hold the control key. Be sure that you've "clicked" into the window otherwise the browser won't be able to tell that you're typing (that's just how browsers work).
** If you want to use this extension on local files (when the URL says file:// at the beginning) you need to go into your Chrome extension settings, go to the Details for the Pesticide for Chrome extension, and turn on the setting "Allow access to file URLs". This is a security setting from Chrome that is off by default.
Pesticide is an open source CSS tool created by Adam Morse and available for download, forking on Github at https://github.com/mrmrs/pesticide
You can follow me here: https://twitter.com/paulmolluzzo