How can I change the background color of the button below.

Here is code you can run and you can see the button background is still white but he color is green

ui.r

```
library(shinydashboard)

dashboardPage(skin="black",
  dashboardHeader(title = "Basic dashboard"),
  dashboardSidebar(
    sidebarMenu(
      menuItem("Dashboard", tabName = "dashboard", icon = icon("dashboard")),
      menuItem("Widgets", tabName = "widgets", icon = icon("th")),
      menuItem(downloadButton('downloadData', label= 'Download', class= "mybutton"))
    ),
       tags$head(tags$style(".mybutton{background-color:red;} .skin-black .sidebar .mybutton{color: green;}") )

    ),
  dashboardBody(
    # Boxes need to be put in a row (or column)
    fluidRow(
      box(plotOutput("plot1", height = 250)),

      box(
        title = "Controls",
        sliderInput("slider", "Number of observations:", 1, 100, 50)
      )
    )
  )
)

```

server.r

```
function(input, output,session) {
  set.seed(122)
  histdata <- rnorm(500)

  output$plot1 <- renderPlot({
    data <- histdata[seq_len(input$slider)]
    hist(data)
  })

  output$downloadData <- downloadHandler(

    filename = function() { 
      paste("test", '.csv', sep='') 
    },
    content = function(file) {
      write.csv(c(1,2,3,4), file)
    }
  )
}

```

code to run app

```
library(shiny)
runApp("C://Users/me/PathToProject")

```

Here is what is returning. you can see the background is white but text is green

[![enter image description here](https://i.stack.imgur.com/2bquQ.png)](https://i.stack.imgur.com/2bquQ.png)