Strange windows 10 theme!! Help change back!!

[vipnower0002]

Greetings! First time asking on this forum so excuse me if I ask in the wrong place.

I don't know how my nephew did this but it's very harsh on my eyes. How can I change it back to normal.
https://imgur.com/SdGdDmA
Edit: I don't know how to post image.

 

[TMTOWTSAC]

That looks like one of the High Contrast modes in the Ease of Access Center. On the right hand side of your image, you can see the option to Turn High Contrast on or off.