Customizations to Responsive Wordpress Site

I need to a freelancer who will make some design changes to a responsive wordpress website. The changes that would be made must display correctly across devices. The freelancer must test the changes on several devices before delivering the project. Only bid if you have excellent experience with wordpress responsive websites. Communication is very important to the success of a project, therefore, the freelancer must have a Skype account, and be able to work with US timezone, and be readily available to discuss the project's progress. Details of the customization will be given via PM. Thanks N/B: Answer this YES or NO question so I can know that you read the project details. I won't consider your bid if the question is not answered. Question: Do you know bootstrap (YES/NO)?