I think solarpunk is more dark than bright.
Taking electric vehicles as an example: Electric vehicles are great and should replace nearly all fossil powered vehicles. But at the same time, the amount of vehicles should be reduced significantly. This can happen trough better public transport, but also by reducing the need to go places, especially related to consumption and work. In my opinion, this can only work with a shift in the way our economy works.
Ah I mixed up light and bright haha
But I still think solarpunk may be a bit darker than even "bright", as technology is not only the tools to make the change, but technology is one aspect of it and direct change in the political and economical system is needed as well.