Bootstrap v4.0.0-beta.2 发布了，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。

　　此次更新的亮点有：

• 　　Improved Sass map customization with #23260. With this change, it's now possible to override specific key value pairs instead of resetting the entire map, ideal for color scheme customization.
  
• 　　Restored grid .offset- modifiers in #23445. Originally our intent was to supplement this with our margin utilities, but we underestimated the appeal of fixed number column offsets.
  
• 　　Remove unnecessary color from .badge, and it's associated $badge-color variable, in #23529.
  
• 　　Rename grayscale function to gray to avoid breaking CSS native grayscale filter in #23579.
  
• 　　Renamed .table-inverse, .thead-inverse, and .thead-default to .*-dark and .*-light, matching our color schemes used elsewhere in #23560.
  
• 　　Responsive tables now generate classes for each grid breakpoint, meaning we've added .table-responsive-{sm,md,lg,xl} to the already present .table-responsive. You might need to adjust your usage depending on when you want a table to resize. See #22804.
  
• 　　Include two new dist files which contain Popper.js inside bootstrap.bundle.js and bootstrap.bundle.min.js. See #23735.
  
• 　　Dropped support for Bower as they've deprecated the package manager. See #23568.
  
• 　　Switched breadcrumbs from float to flexbox in #23683.
  
• 　　Added new CSS variables in #23761.
  
• 　　Switched to Stylelint in #23572.
  
• 　　New Theming page in the docs from #23611
  
• 　　#23943: Changed the color-yiq from a mixin that included the color property to a function that returns a value, allowing you to use it for any CSS property. For example, instead of color-yiq(#000), you'd write color: color-yiq(#000);.
  
• 　　New and improved theming in #24429.
  

完整内容请查看。

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