Getting DE colours in email programs

I am running pop os 22.04 with plasma DE. In desktop I have chosen the Mirage global theme and its related sub-categories. for the longest time these same colours were showing up in Thunderbird and Evolution email programs ( sorry but I quite liked the splashy colours!!) . For some reason they have disappeared from the email programs and all i have are the very drab black and white colours. I was under the impression that “application menu” setting had to be a GTK theme , but that doesn’t seem to change anything. Any ideas?