I'm running Mac OS X El Capitan v. 10.11.6 and Safari v. 10.0.3 Looks like Wilders is a little out of alignment running Safari on the Mac with the vB 3.x - Fluid Forum Style. Flat_Awesome and XenFord Standard Forum Style have no problems, look good.
LWM answered similar queries (about Opera 12) here: https://www.wilderssecurity.com/threads/problem-with-opera-12.391668/
It looks like the Forum is back to normal on my Mac using Safari Browser. It had to be a setting on my computer, which one, I don't know. But today I'm seeing the forum perfectly aligned.