Css minimal styling + sell landing page

Hello to all! What i need is a quick and well done minimal styling for a website in order to make it looks more professional and makes users confident to buy my products. Also i need a landing page for adv campaigns with an attractive but minimal design. Colors are White ,black and green The website is [login to view URL] The work has to be done the following way: 1) you save a page from the website (not index because some css elements are missing) any page but index is good. 2) make your modification offline just with html and css (you can also add images, but trying to not exceed a reasonable size for a fast site). 3) you show me you work (a picture is good enough) and i have to approve it. It's a very small project for an experienced web designer. I would like to be fast because the site is already making visits, but it is not converting yet :( Thank you!