Bootstrap v4.0.0-alpha.4 发布了，这个版本主要的变化是用一个小的"alpha patch" 来命名一个没有任何JS文件的npm包，并且对我们的 CSS 和 docs 进行了一些小小的改变。 CSS #20130: Make .bg-inverse use the background variant mixin for proper text color. #20333: Update progress bar to use $progress-border-radius instead of $border-radius. #20387: Use $input-border-radius-* variables on .input-group-addons instead of $border-radius. #20413: Remove unused $size parameter from grid mixin. #20447: Make cards block level in columns. #20469: Remove non ASCII character from table CSS. #20485: Use rem units on Alert's dismiss icon. #20545: Removed the inconsistent margins between flex and non-flex modes from .media. Replaced them with spacing utils in our docs examples. #20597: Removed unused variables in some grid mixins. #20619: Ensure hover effects work on text utilities. #20629: Update form checkbox and radio styles for validation; tweak docs to match. Docs #20282: Fix typo in Migration docs about Reboot and unit changes. #20341: Update static tooltip demo in docs to use proper class names. #20417: Import the flexbox utilities into the docs flex stylesheet to fix broken flex utility docs. #20475: Update flexbox grid docs to show auto-sizing of sibling columns when using a centered, odd-count column. #20476: Remove CDN coming soon notice from docs page. #20484, #20489: Fix segmented button in input group examples. #20505: Update migration guidelines for renamed table variants. #20519: Add migration note about .panel-group. #20551: Ensure progress component table of contents renders. #20553: Properly size split dropup variation with modifier class. Packaging #20385, #20418: Fix for npm not having a JS directory. #20394: Point package.json's main to proper JS file for package managers. 下载地址：bootstrap-4.0.0-alpha.4-dist.zip Bootstrap v4.0.0-alpha.4 发布下载地址
