I compared your image to my experience in my Chrome browser - and I notice they are pretty much the same ratio and my display doesn't appear changed recently.
You mention that the spacing on the sides are not usually there - the content-width for the forum interface is set to max out for best layout using a 1280x720 resolution monitor (and has been for awhile), centered and padded with spaces on left and right. If you don't normally normally see the site in this way, your image is about 1900 pixels wide and that would suggest your monitor is set at 1920x1080 resolution.
Did you recently change your monitor resolution?
Also, if you have read those months-and-months-old messages pinned at the top of EVERY page of your F95 experience... you can get rid of them by clicking the "X" on the right side of the messages:
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