While people, including myself, have been enjoying Bootstrap 2, the developers have spent the last 9 months working on Bootstrap 3 and today they have announced that it is ready for prime time. Now, the big change is in design philosophy; Bootstrap 3 is “mobile first” which means that rather than having base styles for desktop displays and styling them down into tablets and mobiles, the base styles are for tablet/mobile devices and are styled up for desktop displays. The effect this has on the grid model is explained by Erik Flowers in his blog post “Bootstrap 3 Grid Introduction“.
The more visible change is with a new “flat” design and an optional theme to show off customisation of the visuals. The framework customiser application that previously ran on Heroku has now made the leap to running into the browser and supports sharing of customisation through GitHub Gists. The glyphs which made adding icons quick in Bootstrap have returned as a font and now come with 40 new ones. The navigation bar is now responsive and rearrangable, modal dialogs respond better on mobile devices, there’s added panels and list groups, new documentation, and some components have been retired. Also retired is support for IE7 and Firefox 3.6.