...fyi anyone else using this thread:
When I changed the background using the code above .sqs-announcement-bar-url then the text disappeared and I also couldn't change the text color. But when I used the code .sqs-announcement-bar nothing happened. The solution was to change the background using the code .sqs-announcement-bar and add !important. At that point my text reappeared and I was able to change its color as usual in the site styles area without additional code.