The UI is very low contrast. I think a higher contract rendering would be easier to parse / read
I just checked with one of the WCAG tools and the UI passes with a 12.75 score.
Can i ask which area of the UI you are looking at?
The graph UI. I don't think it's sufficient to be an accessibility issue, however the contrast between the background and boxes seems very low, as well as title bars. See Action node in particular. Light green and box around Flow are very close to the background.