Solved All posts full-width in mobile devices.

Posts in mobile are having space in either side, I would like content to stretch onto that as well. I would like posts to be full width on only mobile/small screen devices.
Thanks in advance. Website link.

 

It's working, but there is a small problem.
My site has 2 kinds of posts: Full Width and Sidebar.
In a previous thread I asked for CSS code to make Full-width posts full width, and I am using that code for full-width posts individually.
Now that I am this code on all pages (code pasted in Theme > Custom CSS), my full-width pages on mobile which already has another CSS code are looking cut off.
One solution I know is to individually paste the code for full width and sidebar posts. The amount of sidebar posts is really high and full width is low. I am okay with pasting individually for full-width posts. It's a little hard for all posts.
I am hoping you could add more code to this so that doesn't interfere with the code you just gave and I could use this code individually for all full-width posts. If this is hard to do, its fine, I am okay with individually pasting codes for all.
Thanks in advance.

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Thanks, it worked perfectly.
I like the way you think to solve the problem.
I feel bad for asking help for small problems. Can you direct me to a source where I can learn all these CSS and stuff?