Customize shopify password page.

I'm about to launch a new shopify store. But I want to customize the password page to let people know about my store and even do some promotion on the page before I launch the store. Details about the promotion： The promotion is quite simple, when people come to the password page, they could subscribe from us. The moment after they click subscribe, they can see a coupon on the page, the coupon will be effected on a certain day, an email will also be sent to their email to tell them how to use the coupon. Besides subscribe from us, they can also submit their name and address to us in order to get a free gift. The basic design of the page could be the same as this one: [login to view URL] My new store will be a fashion store. Thanks.