Convert HTML Templates and CSS to Duplicate Design Of Current 3D Cart Website

Need a person familiar with CSS, HTML, HTML5 to modify a set of HTML templates and style sheets so that the layout, colors, graphics, match the current live version of our website. This is for a 3D Cart store. We are changing the templates we use because the new set of templates is user device responsive and is more mobile / tablet friendly. I do not want there to be any down time on the live site. You can work offline and use the current design style sheets and templates to compare to the new templates and make the changes to the new set as needed. We can then make the new set of templates live and make any final minor adjustments. Upon completion of the change over to the new template set, we will need to run a webmaster test for mobile compatibility using google's webmaster tools and make any changes / corrections to the style sheets, templates as necessary to pass those tests. These shouldn't be much, if any at all, as the new set of templates was built with this compatibility in mind.