Tonight on October 23rd, 2023, we installed updates to our forums software on https://forums.sonic.net/. In addition to the forum and backend software upgrades, our forum style (appearance) also got minor updates.
The default style for all forum accounts was set to the new theme as part of the upgrade. If you wish to change back to the forum default, go to the user control panel and change your board style to prosilver at https://forums.sonic.net/ucp.php?i=174.