Bootstrap 3 RC1

Bootstrap 3 RC1 was released two days ago and from a quick look through the changes and the code, it all makes a lot more sense to me.

Here are some of the changes that seemed interesting to me:

The changes

The biggest change and improvement I recon, is that the framework became mobile-first and thus requires less (not a pun) overrides when using it for your responsive project.
Because of this choice, the grid has been simplified a lot since you start from a single-column layout and go on from there.

Naming formats became more clear and consistent as they now have a scheme using dashes, based on element, state, pseudo state. E.g. @navbar-link-color-hover.

The new grid uses different classes for the columns. The span* classes were replaced with col-* classes which make more sense semantically and match the updated naming format.

Support for IE7 was also dropped which lets you drop all the * hacks from your stylesheet.

The team refactored some of the mixins by dropping obsolete vendor prefixes for border-radius etc.
A nice addition on the other hand, are the updated gradient mixins for better color stop support by adding extra values (@start-percent and @end-percent).

A logical step was to drop glyphicon images and replace them with the glyphicon icon font. Along with this update, they've dropped the icon-* class and replaced it with glyphicon-*.

And at last, one of my favorites is the new mixin for retina image support with .img-retina().

There are a lot of other new features and updates which you can find in the detailed changelog.


Bootstrap now uses Jekyll and Grunt for their docs which I think is great. If you haven't used Grunt yet, you'll experience that it's a very handy tool for compiling .less files, minifying JavaScript and more. Check out my post on getting started with Grunt if you want to know more on what it can do for you.

Get started

The Bootstrap-team decided to move the repository to with all of it's history. At the time of writing this post, the master branch still contains the v2 version, so you'll have to do a checkout of the 3.0.0-wip branch to get the code or download it from

The examples have been moved to a separate repository as well, as the team explained in the v3 pull request.

Here's the link to the official Bootstrap release post of RC1:

Please contribute and test this awesome thing!