On Content area right side is blank need to fix.

I had created the content of article content type and there I see that there is no issue like this.
here I am attaching the screenshot which gives the idea that there is no issue like this.

@alok_singh, I have installed colonel theme in Drupal 9.5.19 and created articles. I am also getting space. But its a sidebar block created in layout. I have added the screenshot for you reference.

I am also getting the blank from the right side. Attaching the screenshot for your reference

here is the MR: https://git.drupalcode.org/project/colonel/-/merge_requests/16
I have hidden the sidebar for content nodes so that the content area is expanded. Upon exploring the page.html.twig template, I noticed there is a section for the sidebar, suggesting that there is a need for it in the theme. Therefore, I imposed the condition that only the homepage and node content should not have a sidebar; otherwise, all other pages should have one. If you want the sidebars removed entirely, you can delete the sidebar lines from the page.html.twig template. Additionally, we can remove the content from the sidebar region in Structure > Block layout.

Hello,
I think there's no problem regarding this in the theme, as different blocks are placed on the sidebar_first region that's why the space was getting occupied. The page.html.twig also correctly implements conditional rendering for the sidebar blocks. Hence, if anyone wants to show their main content in full width view, they must place blocks according to that in specified regions defined in the theme, which can be easily manipulated from UI in the block layout.
As per my configuration the search form was getting rendered initially on the sidebar, as a result the space was getting divided b/w the main content and the sidebar and on removal of that the main content is taking full width.
So as per my findings there's no issue in terms of styling of twig's conditional rendering.

Hence as of now I'm closing the issue. Please feel free to reopen the issue, if you land upon any other conclusion.
Attaching both the screenshots for reference