Background color for status field

Hello ,

  
I want to display green background color to the status field with font color as white in the sales order screen. I Followed Two methods for that,
 1)Method 1: By using below code in  this i obtained colour for status value not in the background, i need background colour for the status field and letters are in white colour. 
          

  <px:PXDataSource>
           <ClientEvents CommandPerformed="changeStatusColor" />
       </px:PXDataSource>

 <script type="text/javascript">
        function changeStatusColor(sender, e) {
            var edStatus = px_all["ctl00_phF_form_t0_edStatus"];
            var edStatusControl = document.getElementById("ctl00_phF_form_t0_edStatus");
            if (edStatus && edStatus.value == "H")
                edStatusControl.background.color = "#FF0000";
            else
                edStatusControl.style.color = "#00FF00";
        }
    </script>

Method 2: Using this method, I received no updates to the field. in this case, I make CSS under the Visual Studio App_Themes folder, as shown below.
   
ASPX:
  <px:PXDropDown ID="edStatus" runat="server" DataField="Status" Enabled="False" CssClass="CustomAMIClassGreen" ></px:PXDropDown>

.CSS
  
    .CustomAMIClassGreen

{
    background-color: green;
    font-weight: bold;
}
      

Can anyone suggest the solution for this?