I use b-table in an application that I'm building and want to change the table head using thead-variant. When I set the value dark or light to thead-variant it works fine, but when I use the other variants like primary, info, danger, ... they don't work for me.

the versions that I use are:

Bootstrap: 4.3.1
Bootstrap-vue: 2.0.3
Vue: 2.6.10