White border (needs to be removed)

Hello,

my website is: http://www.unionpiscines.gr as you can see in the image there is an annoying white border coming up from nowhere.
Moreover when I try to use tabs the tabs appear in this white box, and when I don't use the tabs (you change the language to BG, I don't have tabs in that language you will see this white border).

How can I remove this?

You get this box only on homepage yes? It is caused by fact that you don't have any article on homepage and any module on mainbody position. The best way is to hide this area using this tutorial How to Disable Content on selected Joomla Pages ?

Yes, it happens on homepages because I have no articles. I followed the tutorial but it's still there. Moreover I check the source code of the website and the noMainbody class appears.

Is there any chance that the override.css doesn't work because I have copies of the template? (I coppied the template to use two languages)

Moreover the tutorial has a result to remove the gk-tabs module which is in mainbody and the white border still persists.
Wanna give you an admin code to take a look?

I've visited your website and can't see this part. Please look at my screenshot, where I can see this area which you want to remove?

Check here: http://unionpiscines.gr/bg/ when I use the module GK tabs the module appears in this white box

By default our template has suffix 'nobg' for the 'Home' menu item which removes the background from the tabs module, please apply the same suffix using 'suffix for pages' option and you will get the same effect.

By default our template has suffix 'nobg' for the 'Home' menu item which removes the background from the tabs module, please apply the same suffix using 'suffix for pages' option and you will get the same effect.

wow that's it! All fixed! thanks a lot

In our documentation you will find detailed template configuration it is always worth to compare your settings with the default ones.