Clearblue advanced digital ovulation tests

Hi there. I am curious which is the test line and which is control line on the advanced digital ovulation test.

Are these lines similar to other ovulation tests in which if the test line is the same color or darker than the control line, that means positive and close to ovulation?

I tested today for the first time this cycle and received the empty circle (low), but one line (I believe the test line) was much darker than the control line. Wondering if the digital test holder isn’t working.

Thank you!