Remove main. Use application.scss instead

app/assets/stylesheets/application.css

-/*
- * This is a manifest file that'll automatically include all the stylesheets available in this directory
- * and any sub-directories. 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.
- *= require jquery.ui.gitlab
- *= require jquery.atwho
- *= require chosen
- *= require_self
- *= require main
-*/

app/assets/stylesheets/main.scss → app/assets/stylesheets/application.scss

+/*
+ * This is a manifest file that'll automatically include all the stylesheets available in this directory
+ * and any sub-directories. 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.
+ *= require jquery.ui.gitlab
+ *= require jquery.atwho
+ *= require chosen
+ *= require_self
+*/
+
 /**
  * GitLab bootstrap:
  */