Bootstrap 4.0.0-alpha.2 发布

Bootstrap是快速开发Web应用程序的前端工具包。它是一个CSS和HTML的集合，它使用了最新的浏览器技术，给你的Web开发提供了时尚的版式，表单，buttons，表格，网格系统等等。

• 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.

• Renamed .img-responsive to .img-fluid 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).

• 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.

详情请看：blog post

下载地址：v4.0.0-alpha.2