bring back responsive sidebar overlay

[jtauber]

Like Perseus Scaife, sidebars should overlay rather than push at narrow screen widths.

[mjhea0]

Have you thought about maybe combining them into a single sidebar for mobile views?

[jtauber]

@mjhea0 no, but that's brilliant. There were reasons not to do it in the current Scaife but with this new skeleton approach, your suggestion is probably the way to go.

It might complicate skeleton config, although to be honest I haven't even considered skeleton config on narrow screens yet.

[jacobwegner]

I came across this issue while looking into backporting scaife-viewer #407.

Here are some screenshots comparing current scaife with the skeleton at various resolutions:

Phone

Tablet

Laptop

Desktop