constructor theme customised multiple backgroud images

I love constructor. version 1.0.6
I have created a site with customised static page background image that is small and works for most of the sites content here. I wish to have an alternate background for blog page and individual posts that is seamless so that the posts or blog is covered (here is an example http://write4you.biz/business-awards-season.
I have had some good results using “Custom Post Background” plugin on individual post pages but it has no effect on the main post page (see http://write4you.biz/blog ).
Is there any simple way to customise the css so that blog pages and posts have a different background image to the main theme background image?
Thanks
jerel