Stand alone web page

Hi, I am looking to have a landing page created that can stand alone at the back of any client's website, whatever the platform their main site is on. I'm assuming this would be a HTML page that I can just drop into a /folder and send the traffic there?

Attached is a pdf called 'style' which is how the format/layout of the page can be, I would like to have the ability to change the images, text and colour ideally. I'm not a coder but I would be able to change colour codes and image references if need be in an already HTML coded page, I want this to be a stand alone page without any unnecessary WP install running for it.