Hi there,
Each stack may have different options regarding the color of the Navbar. You can access the stack options by going to X > Launch > Options > {Stack Name}.
It will be helpful if you get back to us with the URL/User/Pass of your website using the secure note functionality of the post to be able to give you exact directions.
To follow up the color of the navbar you are more than welcomed to reply here, for the additional questions kindly open up separate threads so we can focus on each case individually.
Thank you.