New Bootstrap 4 alpha

Bootstrap 4 alpha 2 is now available. Since our last release, nearly 100 people have pushed over 900 commits to v4 and we’ve closed over 400 issues and pull requests. Those numbers are outrageously awesome to see, and we’ve still got a ton of work ahead of us this year for v4.

As mentioned in our last post, the general plan for v4’s development starts with a few alpha releases. We’re a little behind on that, but should be getting caught up as the year winds down. Expect another alpha or two this month to really round things out.

Here’s a look at a handful of the changes since our last alpha:

Overhauled spacing utilities to use a numerical tiering (to avoid confusion with grid tiers).

Continued refactoring efforts to replace markup-specific selectors with classes across several components (including pagination, lists, and more). Still more to do here with additional components.

Reverted media queries and grid containers from rems to pixels as viewports are not affected by font-size. See #17403 for details. We’ve got a ton of grid work left, too. Feel free to follow along with #18471.

Reverted .0625rem width borders to 1px for more consistent component borders that avoid zoom and font-size bugs across browsers.

width borders to for more consistent component borders that avoid zoom and font-size bugs across browsers. Renamed .img-responsive to .img-fluid to avoid future confusion on the various responsive image solutions out there.

to to avoid future confusion on the various responsive image solutions out there. Replaced ZeroClipboard with clipboard.js for Flash-independent copy buttons.

Inputs and buttons now share the same border variable to ensure components are always sized similarly.

Updated all pseudo-element selectors to use the spec’s preferred double colon (e.g., ::before as opposed to :before ).

as opposed to ). Cards now have outline variants and mixins to support extending base classes further.

Utility classes for floats and text alignment now have responsive ranges. This means we’ve dropped the non-responsive classes to avoid duplication.

Added support for jQuery 2.

And hundreds more Sass improvements, bug fixes, documentation updates, and more.

We highly encourage folks to skim through the second alpha’s milestone on GitHub for a better idea of what’s changed across the board. You can also follow along with other v4 efforts with the v4 label on our issue tracker.

Ready to dive in? Then head to the v4 alpha docs!

Be sure to join our official Slack room! and dive into our issue tracker with bug reports, questions, and general feedback whenever possible.

<3,

@mdo & team