Apply conditional formatting to a column based on another column's value in Shiny

Question

I would like to perform conditional formatting on a table for output in a Shinydashboard app (will include a button to allow for pdf download)... but here's the catch, I would like to select colors for cells depending on another value.

In my use case, I have 3 columns per year, an Actual, Target, Percent. Depending on the value of the Percent (90%+,80-89,79-), I would like to highlight the Percent, Actuals and Target columns green, yellow, red.

Here's my data:

a <- tribble(
        ~Item, ~X2015_Actual, ~X2015_Target, ~X2015_Perc, ~X2016_Actual, ~X2016_Target, ~X2016_Perc,
  "Item 1",          1554,          2000,       78,          2100,          2500,       84,
  "Item 2",          5565,          5000,      111,          4000,          6000,       67,
  "Item 3",            12,            13,       92,            12,            15,       80
  )

And here's the expected output:

But I don't know any way to make the comparison based on another column. Any recommendations?

I can do it with condformat, but that doesn't seem to work in Shiny?

library(condformat)
    condformat(a) +
  rule_fill_discrete(X2016_Actual, expression = sapply(X2016_Perc,
                                                       color.picker),colours=c("0" = "white", "1" = "red", 
                                                                               "2" =  "lightyellow", "3" = "lightgreen")) +
  rule_fill_discrete(X2016_Target, expression = sapply(X2016_Perc,
                                                       color.picker),colours=c("0" = "white", "1" = "red", 
                                                                               "2" =  "lightyellow", "3" = "lightgreen")) +
  rule_fill_discrete(X2016_Perc, expression = sapply(X2016_Perc,
                                                       color.picker),colours=c("0" = "white", "1" = "red", 
                                                                               "2" =  "lightyellow", "3" = "lightgreen"))