Thanks for pointing this out. I came across paged.js but for some reason thought it wasn't implementing the margin boxes – I think I just searched their documen

Thanks for pointing this out. I came across paged.js but for some reason thought it wasn't implementing the margin boxes – I think I just searched their documentation page for @top-center and didn't find it. Looking again, I see that they definitely do. Something to check out next time I do this.