[HxSidebar] Multiple levels of nesting

[StefanOverHaevgRZ]

We'd like to use the sidebar with multiple levels of nesting:

We tried to build a recursive menu with multiple levels of depth. However, elements beyond the first nesting don't receive any further indention, and the chevrons don't line up as expected:

There would be plenty of ways to work around this with inline styles etc, but a out-of-the-box solution would be great.

[hakenr]

This isn't currently a top priority for us since there are many aspects we need to address, particularly the mobile view and so on. If anyone is interested in taking this on and submitting a PR, your assistance would be greatly appreciated.