How to change the black background color of Gionee gn500 1s mobile phone?

The black background color of Gionee gn500 1s mobile phone may be because you have turned on the extreme power saving mode.

Specific operation:

Enter the setting interface, click Power Management, and then click Power Saving Management.

Select extreme power saving mode in the power saving management interface. When it is turned on, it will enter the extremely power-saving interface. If you want to quit, just click Exit Extreme Energy Saving.