<%= stylesheet_link_tag "application", :media => "all" %>
我在 layout 中把这句话去掉，然后背景图片就不显示了。。。
我后来在 stylesheets 文件夹里建了个 xxx.css，里面是：
- This is a manifest file that'll be compiled into application.css, which will include all the files
- listed below.
- Any CSS and SCSS file within this directory, lib/assets/stylesheets, vendor/assets/stylesheets,
- or vendor/assets/stylesheets of plugins, if any, can be referenced here using a relative path.
- You're free to add application-wide styles to this file and they'll appear at the top of the
- compiled file, but it's generally better to create a new file per style scope.
然后在 layout 文件中这样用：
<%= stylesheet_link_tag "xxx", :media => "all" %>
多余的 css 没了，但是我的 div 的 background-image 也没了。。。