I just saw a demo on the Page Inspector inside Visual Studio 2012. This is amazing. When you get a chance check it out.

Just right click on the page and view in Page Inspector. You get an ‘F12 Tools’-like interface in which you can check and change CSS and find out whether it’s in the Master Page or the Page itself – all in the one interface.

It’s like the F12 tools on steroids all inside Visual Studio!