1. Leading transparent — transparent → #f8f9fa (Wikipedia bug)

canvas
DOM

2. Trailing transparent — #f8f9fa → transparent

canvas
DOM

3. Interior transparent, same neighbors — red → transparent → red

canvas
DOM

4. Interior transparent, different neighbors — red → transparent → blue (split stop)

canvas
DOM

5. Consecutive leading transparents — transparent → transparent → blue

canvas
DOM

6. All transparent — transparent → transparent (nothing to borrow)

canvas
DOM

7. No transparent stops — red → blue (pass-through, no adjustment)

canvas
DOM