Multiple apps use the same login page before sending your customers to their personalized portal. This page automatically pulls in your logo and uses your Brand Colors, so most of the time it is good to go out of the box.
But if you want to change it up a bit, go to Settings > Options > Portal Login tab.
Any color input with grey text is pulling from your Email Template and Brand Colors. You can override these values by inputting a new HEX code for any color.

