Board Thread:Support Requests - Designing Your Wiki/@comment-35289850-20200816172211/@comment-45117243-20200816173148

Before centering - you have a serious problem there. The width of the borders is defined in percents while the width of the images is defined in pixels.

Well, it's not so serious because the FANDOM layout gives the content area the same width in most cases (Not in all cases. Look at this). But it'll be way simpler if you know exactly what width do you want the border to be.