Oh! That might explain some of the hang-ups we've been having then. Yes, the extension would be necessary for viewing the layout I'm building right now. That said, I can change it up so that you don't have to use the extension if you don't want to, but there will be a lot of differences in the layout's look. The extension is used because it allows more free reign to customize, so without it, there'll be a lot of things I won't be able to do.

So, with that said, if you don't want to/can't use the extension, I'll have to remake the mock-up. There'll also be more installation required on your part but it shouldn't be a problem. I'll talk you through it all. And I do believe I'll be able to put a gradient on the timeline instead of a single color, yes. I'll have to test out a lot of different things to see what does and doesn't work, but background colors shouldn't be an issue.