How I can import Bootstrap 3
Error: No mixin named form-inline
I have only had luck importing it the entire suite of sass files, and then commenting out components I know I'm not using in the _bootstrap.scss. You may end up with more than you like to prevent errors.
From the bootstrap SASS github:
By default all of Bootstrap is imported.
You can also import components explicitly. To start with a full list of modules copy _bootstrap.scss file into your assets as _bootstrap-custom.scss. Then comment out components you do not want from _bootstrap-custom. In the application Sass file, replace @import 'bootstrap' with: