Minor googleVis maps issue

[Lucas Allen]

I've been experimenting with Shiny by creating a map of standardized test scores using googleVis. I thought I had the kinks worked out, running the app from RStudio, where it works just as I want it to. However, when I posted it to my shinyapps.io account, https://lgallen.shinyapps.io/act_sat_scores/ , the interactive legend bar at the bottom of the screen does not display the gradient in Chrome or Firefox. I'm seeing a black bar in Chrome and no bar at all with Firefox. It seems to only display properly in Internet Explorer.

Would this likely be a problem with my code or an issue of googleVis not playing nicely with certain browsers?  I have shared my code on Github here:  https://github.com/lgallen/act-shiny

Thanks in advance to anyone willing to take the time to take a look.