You make these 3 clean and uncomplex pages responsive by adding media queries. These pages are already coded in Html5 and css
Result must be a clean and nice responsive design for phone, tablet and desktop.
+ Adding responsive images solution. Techniques overview,
Giving webpages the ability to tell the user's device (mobile or not) before the image is requested from the server and using the most efficient image. So helping to improve site speed for mobile.