Since some people missed the pre-Christmas 2011 theme, I made a userstyle to change it back, seeing as it's unlikely Gage would update it again. 
Userstyle: https://userstyles.world/style/27974/old-2011-austiblox-theme
Preview: https://userstyles.world/preview/27974/0.webp
There is already an existing link to this userstyle in #general in the Austiblox Discord server, but seeing as most Austiblox users seem to not use discord, and that #general is generally not a good place to store information long-term, I made the decision to open a thread here.
