Stunning - love your color selection. The yellow square could be a light showing through the fabric.
Bargello has been on my "list" and have had two pattern books for the Bargello for years. Seem to always get side-tracked with a "but first."
A narrow border in the medium dark red and the darkest red for the binding might look nice. I rarely bind a quilt in one of a quilt's lighter colors. Just doesn't look right to my old eyes. LOL