There has been a beta release of the new version of the core software we use, XenForo.
As a result, I have started making various changes necessary for the upgrade.
The first of those is there are now two styles: Fixed and Fluid.
Click on the link in the very bottom left of the footer to switch between the two (it should say Fixed currently).
As the names suggest, one is a fixed width, the other is a fluid width, which will eventually become responsive when we upgrade.
The Fluid style will be the default in the future, so any new members or guests will automatically receive that style.
Members can of course choose which style to use permanently when logged in.
Currently there is no responsive element to the style, it will just shrink to fit smaller windows but feel free to use it in the meantime.
Bear in mind though that it has not been optimised for narrow width screens so won't work well in some cases.