Windows 10 comes with many features, including the option to use Dark Mode for all windows settings and compatible applications.
There is also a Custom option under Choose your color. This allows you to decide when you want dark mode to be the desired setting or to keep the old light settings.
Choose your accent colors below the dark/light mode settings allows you to choose the desired contrast color when using your computer.
If you have any questions or need assistance, please contact your ACES IT Pro. You can find your department's IT contact information here: https://techsupport.aces.illinois.edu/departmental-it-offices