When working through courses, after clicking "enroll" the text changes to "Start". When the course is completed, the word changes to "Completed" and the button changes to light green.
It would be very nice to have the "Start" button be a different color than the "Enroll" button. Especially if the user is scrolling through many courses after they clicked "Enroll" to find the course again.
This seems to be an easy request that would make the learner experience just a little bit better.