Attempting to adjust the width of the post container within my theme has proven to be quite challenging. Despite multiple attempts to modify the style.css file, the desired changes simply won't take effect.
A RIGHT sidebar was successfully incorporated using the "STYLE" plugin, and everything appears to be functioning properly. However, increasing the content width has been unsuccessful thus far. The utilization of a child theme provides some reassurance in this situation.
Attached below are screenshots of my webpage: