Graham bemethavinci it is in the file xtgem_template.css
* {text-align:center!important} the * wildcard tells it to affect all html elements !important tells it to override other settings that come later (unless they are also marked !important)
You can also add it in a <style> tag or any linked css file there are other settings you can add so that it only affects the blog or forum or only affects the mobile view but they are more complicated and would need setting up specifically