问rake中止！Sass::SyntaxError:未定义变量：“$alert-padding.”

EN

            source 'https://rubygems.org'
            gem 'rails', '4.2.3'
            gem 'mysql2', '~> 0.3.11'
            gem 'jquery-rails'
            gem 'jquery-ui-rails'
            gem 'sass-rails', '~> 5.0'
            gem 'bootstrap-sass', '~> 3.2.0'
            gem 'uglifier', '>= 1.3.0'
            gem 'coffee-rails', '~> 4.1.0'
            gem 'jbuilder', '~> 2.0'
            gem 'sdoc', '~> 0.4.0',          group: :doc
            gem 'haml'
            gem 'haml-rails'
            gem 'devise', github: 'plataformatec/devise'
            gem 'html2haml'
            gem 'simple_form'
            gem 'validates_formatting_of'
            gem 'tzinfo-data'
            gem 'therubyracer',  platforms: :ruby
            gem 'twitter-bootstrap-rails'
            gem 'jquery-validation-rails'
            gem 'sprockets-rails', :require => 'sprockets/railtie'
            gem 'jquery-turbolinks'

            gem 'paperclip'
            gem 'fancybox-rails'
            gem 'css3-progress-bar-rails'

            group :development do
              gem 'spring'
              gem 'pry-rails'
              gem 'better_errors'
            end

            group :development, :test do
              gem 'rspec-rails'
              gem 'factory_girl_rails'
            end

            gem 'delayed_job_active_record'

            # Need daemons to start delayed_job
            gem 'daemons'

            gem 'rails_config', '~> 0.4.2'
            gem 'cancan'
            gem 'two_factor_authentication'
            gem 'twilio-ruby'
            gem 'binding_of_caller'
            gem 'rest-client'

  Rails.application.configure do
      config.cache_classes = true
      config.eager_load = true
      config.consider_all_requests_local       = false
      config.action_controller.perform_caching = true
      config.serve_static_files = true
      config.assets.js_compressor = :uglifier
      config.assets.css_compressor = :sass
      config.assets.compile = false
      config.assets.compress = false
      config.assets.digest = true
      config.log_level = :debug

      config.action_mailer.perform_deliveries = true
      config.action_mailer.delivery_method = :smtp
      config.action_mailer.raise_delivery_errors = true
      config.i18n.fallbacks = true
      config.active_support.deprecation = :notify
      config.action_mailer.default_url_options = { :host => Settings.PROD_URL }
      config.log_formatter = ::Logger::Formatter.new
      config.active_record.dump_schema_after_migration = false
    end

    /*
    *= require_tree .
    *= require_self
    */