Yep, the themes.spec is really important there, because it defines the Theme information 
I’m glad it is working for you know!
same error, but im a patient observer, so ill better wait for a more idiot friendly release suited better for me 
Could it be, that the styles folder is missing in your repo?
in "/config/lovelace/decluttering_templates/badge_climate_button_template.yaml", line 83, column 19: Unable to read file /config/lovelace/styles/separator_card.yaml.
Yep! Completely. Let me update the theme
Could you please update the theme repo, copy again the lovelace folders inside your HA config folder, and try again please?
Thanks!
Now it’s the cards folder 
in "/config/lovelace/decluttering_templates/lights_view_button_template.yaml", line 131, column 27: Unable to read file /config/lovelace/cards/lights/card_lights_living_room_lightsview.yaml.