A CSS compatibility patch to make ng-bootstrap work with Bootstrap 3.
Include this after Bootstrap 3 CSS.

• Install ng-bootstrap
• Install Bootstrap v3.3.7
• Install via NPM:

npm install ng-bootstrap-to-bootstrap-3

• Import, require, link, whatever, after Bootstrap 3 CSS. Tested with Bootstrap v3.3.7.

Look for comments in the linked demo, but keep in mind that the approach is always the same:

1. Unlink Bootstrap 4, link Bootstrap 3.3.7
2. Link ng-bootstrap-to-bootstrap-3 CSS patch after Bootstrap 3.3.7
3. Use the markup from Bootstrap 3.3.7 for Angular templates
4. Use the directives, event handlers, and whatever from ng-bootstrap instead of the data-something ones from Bootstrap 3

• Accordion (BS4 structure with BS3 colors and spacing)
• Alert
• Buttons
• Carousel
• Collapse
• Datepicker
• Dropdown
• Modal
• Pagination
• Popover
• Progressbar
• Rating (It just works, no need for a patch)
• Scrollspy (Planned feature of ng-bootstrap)
• Tabs
• Timepicker
• Tooltip
• Typeahead

• (nice-to-have) Demo page a-la ng-bootstrap