Around the Bend

I hope you’re not tired of Region Sum Lines yet. I hope the blue lines aren’t driving you… around the bend!

Rules:
Normal Sudoku rules apply.
Kropki: In cells separated by a black dot, one digit is double the other.
Region Sum Lines: Thick region borders divide each blue line into segments on which the digits have the same sum. Different lines may have different sums.

Estimated difficulty: 3 out of 5