The forum you linked to is using a really old version of a stock UBB.threads style (theme) as its DEFAULT site style. The best way you can help out that forum is to suggest that they update their forums with the current version of that style.
By looking at the default style name on stovebolt, "ubbthreads-stock", they are using a style from around 10 years ago.
Write to your forum admin and ask that they update their default forum style to the current version of that style, which is now named "UBBT70 - Light." This is a basic maintenance task which doesnt seems to have been done on that forum for many years.
"UBBT70 - Light" retains the same general appearance, but its been updated for modern browsers and mobile devices. It also includes several code fixes and all the updates required for displaying correctly with the current version of the forum software they are using.
Stovebolt's current style is from around 2005 - 2007 - "ubbthreads-stock"
The current version of that style is named "UBBT70 - Light" amd it was last updated July 1, 2019
SOURCE:
https://www.ubbcentral.com/forums/ubbthreads.php/topics/261503/stock-ubb-threads-style-packs
