Light and dark theme
MindMaxer comes in light and dark. Dark is the default.
In the app
Open Settings from the app menu and pick Dark, Light or Match device. Match device follows your computer or phone, so it turns light or dark when your device does. The choice is saved to your account and applies everywhere you sign in.
On the website
Use the sun or moon button at the top right of any page to switch. That choice is kept in your browser.