How to optimize css files in c#

Question

I have two css file i.e css1 and css2

 

CSS1.css

body {
font-size:larger;
color:darkred;
margin-left: 15px;
}

And CSS2.css

body {
color:red;
margin-bottom: 100px;
}

And, using this bundling configuration:

bundles.Add(new StyleBundle("~/Content/cssTest").Include(

"~/Content/Css1.css",

"~/Content/Css2.css"));

BundleTable.EnableOptimizations = true;

Getting result

body {
font-size:larger;
color:darkred;
margin-left: 15px;
}
body {
color:red;
margin-bottom: 100px;
}

Expected result

body {
font-size:larger;
color:red;
margin-left: 15px;
margin-bottom: 100px;
}