Past is a skin for the Bootstrap framework. It is a relatively small set of CSS overwrites that change color and style definitions and add some textures here and there. Some other things are also adjusted to my liking (like the line heights) and a different set of fonts is selected, including Arimo from Google web fonts. It has been tested on all major browsers and Internet Explorer 8 too.
The “package” contains 5 files in all, 2 of those are CSS (that are the same but one of them is minified) and 4 PNG files in a different folder. The CSS should be loaded after the main Bootstrap installation since Past overwrites defaults. It was build on top of version 2.3.0 but I don't have reasons to believe that there will be any problem with a previous or even next version. Of course, I will keep it updated! Here follow some screenshots, from the documentation files of Bootstrap.