Is your feature request related to a problem? Please describe.
I see in the demo images that the tab underline can be changed to blue, green, etc. Looking at the options struct however, there isn't such an option. In addition, the underline color doesn't match the selectedTextColor.
Describe the solution you'd like
Either
1/ provide a color option in Underline
or
2/ match the line's color to the selectedTextColor