Open the Settings App.
Go to Accessibility - Colour Filters and disable any color filter that may be enabled.
Go to Accessibility - Contrast Themes and disable any Contrast Theme that may be enabled.
Go to Personalization - Themes.
In there, set the theme to the Default Windows Theme.
Restart (not shut down) your PC to apply the changes.
If that does not resolve the problem, please provide a screenshot showing the problem on your screen.