Hi there, I am sure this is just some stupid small thing but I cannot find it for the heck of me, it has me totally stumped.

On this page here:http://www.erika-ferenczy.at
the background should be black, but it is white and I cannot find out why.

- If the css of the theme was overwritten by the update, then why are all the correct images there?
And main css looks like this:

body {
font:12px Trebuchet MS, Tahoma, Arial;
color:#000;
background:#000;
margin:0px;
padding:0px;

and so on, you can view the source code and go to main css from there, you can see the #000 background. It was blue-green before, I tried to change to balck to see if it takes effect.
You can also go to typography css from there.
When I open a content block to edit, the background is blue-green, like the background I had before I changed to black.

Now in Chrome I can right click and inspect my page.

When I do this it looks like the first picture.
I uploaded the theme, the same css, to another page and now the background is blue-green, and inspect in chrome looks like the second image. You can see on the right that the background colour is shown, whereas is the first pic you cannot see any background color.
I was wondering why. The information from the main css is overruled somewhere.
I'd very much appreciate your help with this.