A single web page - HTML only required

I require a single webpage to be built for one of my clients. It is a simple holding page with the only functionality being that a button will open up the user's mail client with a pre-populated email address (mailto:) and possibly a pre-populated message. The page must be responsive for mobile and you will determine this from the desktop visual. PSD will be provided for assets as will a separate word doc with the correct text (as it has slightly changed from the design). Screenshot of the design is attached. I would need this ideally completed for Friday morning.