default colour in dropdown box in DS 1.5

Hi all,

I have written following code in my custom css file and it is working fine.

.testDD.sapUiTfStd {background: blue; color: white;} 
.sapUiLbxStd li.sapUiLbxI {background: #2f38b2; color: white;} 
.sapUiLbxStd li.sapUiLbxI.sapUiLbxISel, .sapUiLbxStd li.sapUiLbxI.sapUiLbxISel span {background:

#87a5e9; color: #400040;} 
.sapUiTfStd:hover {
background:orange;
}

But, I want that when I first time opens the application; it should show red color selected.

what I have to add in above code??