How to set the red rice note mobile phone to full screen gray?

1. Go to the phone desktop and find "Settings".

2. Pull to the bottom of the setting interface and click "About Mobile Phone".

3. Click "Version Number" for more than 5 times.

4. Just prompt "You are in developer mode".

5. Go back to the settings interface and you can see "Developer Options".

6. Click "Simulation Color Space".

7. Change it to "color blindness" so that the display on the mobile phone will turn gray.