Css 引导变量在rails中不可用

我如何让@screen sm@screen md@screen lg变量工作，而不给我错误？在rails中使用引导sass gem

当我删除@screen sm@screen md@screen lg变量并用像素值替换它们时，浏览器中的错误就会消失。但是当我使用这些变量时，browser-rails错误表示这些参数无效

我正在使用引导SASTS3.0.3

我的application.js文件中还有

/=require bootstrap

。 github页面说这样做会导致变量在其他文件中不可用，但即使我从js文件中删除了这一行，我仍然无法使用application.css.scss文件中的变量

application.css.scss

*= require_self
*= require_tree .
*/
@import "bootstrap";

/* Small devices (tablets, 768px and up) */
@media only screen and (min-width: @screen-sm){ 

}

/* Medium devices (desktops, 992px and up) */
@media only screen and (min-width: @screen-md){ 

}

/* Large devices (large desktops, 1200px and up) */
@media only screen and (min-width: @screen-lg){ 

}

Gemfile

    source 'https://rubygems.org'
    ruby "2.0.0"

    gem 'rails', '4.0.0'
    gem 'uglifier', '>= 1.3.0'
    gem 'sass-rails', '~> 4.0.0'
    gem 'coffee-rails', '~> 4.0.0'
    gem 'jquery-rails'
    gem 'turbolinks'
    gem 'jquery-turbolinks'
    gem 'jbuilder', '~> 1.2'
    gem 'sprockets-rails', :require => 'sprockets/railtie'

    group :doc do
      # bundle exec rake doc:rails generates the API under doc/api.
      gem 'sdoc', require: false
    end

    gem 'html2haml', '~> 1.0.1'
    gem 'haml-rails', '0.5.1'
    gem 'bootstrap-sass', '~> 3.0.3.0'

    gem 'figaro', '~> 0.7.0'
    gem 'nokogiri', '~> 1.6.0'
    gem 'paperclip', '~> 3.0'
    gem 'paperclip-dropbox', '>= 1.1.7'
    gem 'devise'

    group :development do
        # erubis is already included in action pack
        gem 'ruby_parser', '~> 3.1.1'
    end

    group :development, :test do
      gem 'sqlite3'
    end

    group :production do
      gem 'pg'
      gem 'rails_12factor'

      #gem 'aws-sdk', "~> 1.0"
    end

    # Use ActiveModel has_secure_password
    # gem 'bcrypt-ruby', '~> 3.0.0'

    # Use unicorn as the app server
    # gem 'unicorn'

    # Use Capistrano for deployment
    # gem 'capistrano', group: :development

    # Use debugger
    # gem 'debugger', group: [:development, :test]

---

今天我碰到了同样的问题。我认为问题的根源在于混合了语法（Less与sass）

如果您正在编写一个面向较少的样式表，则使用

@

运算符引用变量。而使用scass编写样式表（我推断这是因为文件名

application.css.scss

）变量是使用

$

引用的

因此，您的样式表必须编写如下：

...

@import "bootstrap";

/* Small devices (tablets, 768px and up) */
@media only screen and (min-width: $screen-sm){ 

}

...