Use Style.Add(<css properties here>, <css value here>).
you can add as many css properties as you like.
Examples:
codeDiv.Style.Add("padding", "5px 1px 2px 5px");
codeDiv.Style.Add("border-style", "solid none solid none");
codeDiv.Style.Add("border-color", "Red Yellow Blue Green");
codeDiv.Style.Add("border-width", "1px 2px 3px 4px");