Contrast is greatly reduced in nested state nodes

[robertpenner]

Description

Contrast is greatly reduced in nested state nodes.

Expected Result

Contrast is consistent and state names are easily legible.

Actual Result

It looks like a reduction in opacity or brightness is being applied multiple times with nested state nodes. Look at regular vs. update vs. sec and 1min

Reproduction

https://stately.ai/viz/a71a3fcd-8241-465c-8974-4ce761ae7024