Hey ArcGIS Hub Team,
Just a heads up currently there are a few issues with the tools in ArcGIS Hub:
Background images for Banners do not work-

Image Transparency on background images isn't working-

Hamburger Menu on mobile does nothing-

I opened an Esri support case about these issues but I'm only allowed to troubleshoot one of these issues per case so I've turned to here to alert you.
Thanks,
Amanda