The divider above nav bar is missing

[AnhQuanTrl]

Describe the bug
When I try to use this awesome theme, everything was perfect except one thing:
There is no divider above the nav bar like in the preview:

Expected behavior
There should be a divider above the bottom nav bar.

Screenshots
My current state:

Expected State:

Desktop (please complete the following information):

• OS: MacOS
• Browser: Firefox
• Version: 130.0.1

Additional context
Add any other context about the problem here.

[AnhQuanTrl]

Updates: It seems like the some `@media` query from `sideberry.css` such as:

  @media not (-moz-bool-pref:"af.sidebery.top-new-tab-btn") { 
          border-top: 1px solid var(--separator-color) !important; }

does not have any effect.