Haven’t investigated much further than achieving a desired goal which was to make the filter buttons stand out instead of the normal white button with whatever color Knack uses based on setting.
.tabs.is-toggle a {
color: #f5f5f5;
background-color: #07467c;
}
We have a 20,000 record database of soldiers and to narrow down searches (and makes researchers lives easier when assigned a task of going through them, we have programmed for A to Z buttons on top of the table display. (Users not educated in setting filters themselves).
Works well, took a bit to find which variable it was that could be set without effect on rest of the environment.
Examples
BACKGROUND COLOR HEXCODE #07467c
BACKGROUND COLOR HEXCODE #D93E46
Cheers