Using the black in the middle of the rail gives it wonderful depth, almost 3D-ish.
Depending upon on how I squint, I see either the black floral as the main rail, or the turquoise.
It's such a simple pattern but choosing the right fabric combination elevates it to fabulous.
Instead of the standard Light, Medium, Dark, you did a Light, Dark, Medium, and it really, really makes a difference.
Great job!