gray space problem

i didn't find a solution on how to remove the gray space in this page
http://shakerali.net/new/blog/video.html

to be something like this
http://shakerali.net/new/blog/nm.html

i tried to copy the same element but it didn't work out

Thanks,

You are missing 'no-sidebar' page suffix.

do you mind if u tell me where is locate ?

This article mentions page suffixes:
https://www.gavick.com/documentation/un ... mla-pages/