Enjin has a wonderful module called the HTML module that when paired with the EnjinAPI allows you to alter almost anything on your website.
Specifically to alter pages like the Login Page, Profile Page, and Dashoboard, you'll need to create a system page from your admin dashboard, then use and HTML module to code to your heart's content and make your website look amazing.
In the event that you can't figure it out yourself, feel free to contact me. I manage a company called SmartWebStudios and we have web design plans starting as low as $30 USD. We'd be more than happy to help you out.
Good luck, and happy coding.
-Abyssal Gaming Founder/CEO