[Adelle] Background in posts

I was using Adelle on wordpress.com (danielleharens.wordpress.com) and there is the content *header, posts etc.* on a white background, so that I can have my own custom background without loosing any text to read. I wanted to use Adelle on my www.ads-software.com site but I can’t get my content, like on the wordpress.com on a white background… It looks awful right now..

Can someone help me?
Site: https://www.dh-photography.nl

Thanks!