Shows a single local tree rotation (left and right) transforming an imbalanced BST region into a balanced one. The animation fades out old parent/child links and fades in the new links while keeping the BST in-order sequence (A < x < B < y < C) visibly unchanged. It also contrasts AVL-style balance factors vs Red-Black invariants and connects the local invariant to the global height bound O(log n).
Time-based 4s cycle: alternates left/right rotation each cycle and alternates AVL vs Red-Black explanation every two cycles. Node positions are interpolated between pre/post rotation layouts using the provided cubic ease(). Edges are drawn with orthogonal (blocky) connectors and cross-faded to emphasize which pointers change while preserving in-order order.