title: Background color of tabs in shiny tabPanel
body: <p>I would like to customize a shiny application using <code>tabsetPanels</code> so that the selected panel appears in a black background with white text, and the unselected tabs show a white background with black text.</p>
  
  <p>For example, In the application below, when the "Hello" tab is selected, I would like "Hello" to be in white text on a black background.  But I still want the background of the panel content (the input field) to remain white.</p>
  
  <p>The closest thing I've been able to find come from this question: <a href="https://stackoverflow.com/questions/32233477/tab-box-css-for-shinydashboard">Tab Box CSS for shinydashboard</a></p>
  
  <p>Applying that code yields a colored background all the way across the tabsetPanel, but I still can't find a way to modify this to change the background of only the tabs. Furthermore, nothing I change in the <code>.nav-tabs-custom</code> css seems to take any effect whatsoever.</p>
  
  <p>I'm continually tempted to try applying changes to the <code>tab-pane</code> tag CSS, but that pushes changes into the body of the tab, not the title box.</p>
  
  <p>Any ideas on what I could change to get the title boxes to change background color?</p>
  
  <pre><code>ui &lt;- shinyUI(
    fluidPage(
      tags$style(".nav-tabs {
    background-color: #006747;
      }
  
  .nav-tabs-custom .nav-tabs li.active:hover a, .nav-tabs-custom .nav-tabs li.active a {
  background-color: transparent;
  border-color: transparent;
  }
  
  .nav-tabs-custom .nav-tabs li.active {
      border-top-color: #FFF;
  }"),
      tabsetPanel(
        tabPanel(
          title = "Hello",
          textInput(inputId = "text", label = "Input")
        ),
        tabPanel(
          title = "World"
        )
      )
    )
  )
  
  server &lt;- shinyServer(function(input, output, session){
  
  
  })
  
  shinyApp(ui=ui, server=server)
  </code></pre>