Tap Settings in the Top view.
Select a theme, e.g. Minimalistic or Chrome Rings.
In addition to these themes, you can also choose between Normal and Bright. In Normal, the background of the screen is dark and the text is light. This option is the default setting for all themes. If the bright version is selected, the background will be light and the text will be dark. This option can, for example, make the screen easier to see in bright daylight conditions.
These alternatives are always available for selection and are not affected by the ambient lighting.