I can change the buttons icon color (on the left in the picture), but not the actual button (on the right in the picture).
The code that i use:
(I also tried the # commented lines before, but they didn't work so i disabled them)
frontend:
themes:
dark_green:
modes:
dark:
secondary-text-color: "#A4A4A4"
divider-color: "#333333"
card-background-color: "#141414"
primary-background-color: "#0d0d0d"
primary-color: "#068c5d"
accent-color: "#068c5d"
state-icon-color: "#068c5d"
app-header-background-color: "#13231D"
# ha-button-color: "#FFC0CB" #pink color for testing
# ha-button: "#FFC0CB" #pink color for testing
# button_color: "#FFC0CB" #pink color for testing
# button_text_color: "#FFC0CB" #pink color for testing
# button_color_hover: "#FFC0CB" #pink color for testing
# button_color_active: "#FFC0CB" #pink color for testing
Also in the documents https://www.home-assistant.io/integrations/frontend/#state-color there is no mention of buttons. Only switches, etc...