Steam Store Page Template

It's definitely possible, but that sounds a lot like a phishing scam, and i would recommend not doing anything of the sort. Also there's a high likelihood that the Steam Store visuals will fall under Intellectual Property rights, if you mimic it too closely.

If you need it for a prank or such for a friend, just take a screenshot.

1. Edit a store page via dev tools (right click, Inspect Elements)
2. Save page (right click, save)
3. Open saved page in a browser