Color Scale color for Highcharter maps

Question

I have made a plot of France displaying some values accross departments.

My problem its that I have negative values And Ill like to start the color scale from red to blue (or green), a way to fix it?

Here is my code

hcmap("countries/fr/fr-all-all", data = freq_dept, value = "freq",
      joinBy = c("name", "departmentName"), name = "Fake data",
      dataLabels = list(enabled = TRUE, format = '{point.name}'),
      borderColor = "#FF0000", borderWidth = 0.1) %>% 
  hc_mapNavigation(enabled = TRUE)