CSS inject

Here you can create a Bookmarklet that will apply whatever styles you want on any page you want, useful for client demonstration and bug debunking between peers.

Here goes your css: Bookmarklet name:

Drag the Bookmarklet that will appear below to your bookmarks bar and then use it in the page you want

CSS snippet examples and useful CSS page modifications at Github

Interested in injecting some Javascript instead? You should check JS Inject!