title: Add background image to specific tabPanel in Shiny
body: <p>I use a navbarPage in my shiny application. It permits to create 2 tabpanels. I would like to custom the background of the first tabpanel ONLY.</p>
  
  <p>The best option I found yet consists to create a specific style ("my_style_1") with the tag argument. And then apply it to tabpanel 1 only. My Ui.R code looks like that:</p>
  
  <pre><code>library(shiny)
  shinyUI(navbarPage(
  
      # --- Application name
      "my application",
  
      # --- Creation of a style named my_style_1
      tags$head(
          tags$style(HTML(".my_style_1{ 
                  background-image: url(http://papillondamour.p.a.pic.centerblog.net/fb850229.jpg );
      }"))),
  
      # --- Sheet number 1 wih custom style
      tabPanel( title="Page1" ,
              column(10,
                  class="my_style_1",
                  br(),br(),br(),h1("A piece of text"),br(),br(),br()
              )),
  
      # --- Sheet number 2
      tabPanel( title="Page2" ,
              column(10,
                  "Another piece of text"
                  ))
              ))
  </code></pre>
  
  <p>And the most basic server.R you can do:</p>
  
  <pre><code>library(shiny)
  shinyServer(function(input, output) {})
  </code></pre>
  
  <p>It almost work as you can see <a href="https://i.stack.imgur.com/cCtI9.png" rel="nofollow noreferrer">here</a>. But the image cover only the area of "column", it is not a real background.</p>
  
  <p>If I wanted to apply the same background to every tabPanels, I could just do</p>
  
  <pre><code>    tags$head(
          tags$style(HTML("body{ 
                  background-image: url( http://papillondamour.p.a.pic.centerblog.net/fb850229.jpg );
      }"))),
  </code></pre>
  
  <p>And I would get this good result: <a href="https://i.stack.imgur.com/XYl2w.png" rel="nofollow noreferrer">here</a></p>