title: Custom color for ICellStyle FillForegroundColor than provided named colors
body: <p>We are newly started using NPOI components. </p>
  
  <p>We are having issues to set FillForegroundColor of ICellStyle property. </p>
  
  <pre><code>ICellStyle HeaderCellStyle = xssfworkbook.CreateCellStyle(); 
  
  HeaderCellStyle.FillForegroundColor = NPOI.HSSF.Util.HSSFColor.RED.index;
  </code></pre>
  
  <p>FillForegroundColor expects of type short. </p>
  
  <p>How do we set a different color rather than using colors in HSSFColor. </p>
  
  <p>We need to set to <code>"RGB192:0:0"</code> and how do we do that for ICellStyle property FillForegroundColor </p>
  
  <p>Colud someone help us by some example?</p>