title: R Shiny box content background color
body: <p>I am trying to change the background content colour of my box from white to #222d32 (or any custom colour), however when using the <code>background</code> parameter I get the error </p>
  
  <blockquote>
    <p>Error in validateColor(background):    Invalid color: #222d32. Valid
    colors are: red, yellow, aqua, blue, light-blue, green, navy, teal,
    olive, lime, orange, fuchsia, purple, maroon, black.</p>
  </blockquote>
  
  <p>Code below:</p>
  
  <pre><code>library(shiny)
  library(shinydashboard)
  
  ui &lt;- dashboardPage(
      dashboardHeader(),
      dashboardSidebar(),
      dashboardBody(
          fluidRow(
              box(width = 6, title = "test", status = "primary", solidHeader = TRUE, background = '#222d32',
                  "Box content"
              )
          )
      )
  )
  
  
  server &lt;- function(input, output) {}
  
  shinyApp(ui, server)
  </code></pre>
  
  <p>I have also tried to create a custom wrapper to catch the <code>&lt;div&gt;</code> and modify it, however was not successful. Code below:</p>
  
  <pre><code>library(shiny)
  library(shinydashboard)
  
  box_customBackground &lt;- function(box_object, color = NULL){
  
      new_color_class &lt;- paste0('&lt;div class="box box-solid ', color ,'"&gt;')
  
      box_modify &lt;- gsub('&lt;div class="box"&gt;', new_color_class, box_object)
  
      box_html &lt;- HTML(box_modify)
  
      return(box_html)
  }
  
  
  ui &lt;- dashboardPage(
      dashboardHeader(),
      dashboardSidebar(),
      dashboardBody(
          fluidRow(
              box_customBackground(box_object  =  box(
                  actionButton(inputId = 'SelectGroup', label = 'Change Groups'),
                  checkboxGroupInput(inputId = 'SimulationType', choices = c('Growth', 'Step'), selected = 'Growth',
                                     label = NULL, inline = TRUE),
                  width = 5), color = '#222d32'
              )
          )
      )
  )
  
  
  server &lt;- function(input, output) {}
  
  shinyApp(ui, server)
  </code></pre>