A custom stylesheet for use with Ruben Bakker’s Mac OS X Gmail application, Mailplane. In a nutshell, the style sheet simply cleans up most of the unwanted fluff in Gmail:
Enable Custom Stylesheet in Mailplane
To enable the custom stylesheet, select the “Tweak UI” option in Mailplane preferences then click the “Use custom stylesheet” option, and navigate to where you plan to store the stylesheet on your computer. Personally, I keep a copy of the stylesheet in my Dropbox Documents folder, so it’s always up to date whether I’m in the office or at home.
The mailplane_clean.css file is free to use and modify, is and released under the Creative Commons GPL 2.0 license. http://creativecommons.org/licenses/GPL/2.0/