Thanks for your reply Tony, but this is the opposite of what I want.
I want the sidebar to look like this https://www.soulart.nl/NIEUW/blog/86-blogpost-1
I did this for all pages, but only https://www.soulart.nl/NIEUW/blog has the ‘original’ style. So I want the blog to be the same as the other pages.
Regards,
Remco