SharePoint Online - Bootstrap Resources

ShareBoot - http://www.topsharepoint.com/shareboot-responsive-sharepoint-2013-theme#comment-142954

BindTuning - http://www.bindtuning.com/

Responsive SharePoint

• https://responsivesharepoint.codeplex.com/
• http://bastiaanjacobs.nl/2014/01/30/sharepoint-2013-responsive-mpb-bootstrap/ 

Making seattle.master responsive - http://blog.sharepointexperience.com/2015/03/making-seattle-master-responsive/

Avoid CSS Ricochet-
https://melcher.it/2016/03/bootstrap-sharepoint-online-avoid-css-ricochet/