Bootstrap 4.0.0-alpha.2 发布，更新如下：
- 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.
.0625remwidth borders to
1pxfor more consistent component borders that avoid zoom and font-size bugs across browsers.
.img-fluidto 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.,
::beforeas 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 none-responsive classes to avoid duplication.
- Added support for jQuery 2.
- And hundreds more Sass improvements, bug fixes, documentation updates, and more.