title: r DataTables (DT) border width / colour
body: <p>Given the table </p>
  
  <pre><code>library(DT)
  
  datatable(
    iris,
    style = "default",
    filter = "top",
    class = "hover stripe compact"
  )
  </code></pre>
  
  <p>I can adjust the footer border using the following css</p>
  
  <pre><code>table.dataTable.no-footer {
      border-bottom: 1px solid #ddd;
  }
  </code></pre>
  
  <p>However I can't seem to understand how I can change the border under the column names, nor the border just over the first row of the body. How could this be done?</p>