C#

[DllImport("sn25.dll", EntryPoint = "****")] 
static extern int snod(string host, string port, 
                       string user, string passwd, 
                       string cert, string CAert, 
                       string Nodtjänst, string arg, 
                       string extra, 
                       StringBuilder result, int buf);

// create a 1K buffer
StringBuilder sb = new StringBuilder(1024);
int res = snod(............, sb, sb.Capacity);
string resultStr = sb.ToString();

string input = @"#DTEST 
                    { 
                        border-style:solid;
                        border-width:thin;
                    }";

string pattern = "[\n\t\\s]*[a-zA-Z\\-]+[\\s]*:[\\s]*[a-zA-Z\\-]+[\n\t\\s]*";

MatchCollection mc = Regex.Matches(input, pattern, RegexOptions.Multiline | RegexOptions.IgnoreCase);
Console.WriteLine(mc.Count);
foreach (Match m in mc)
{
    Console.WriteLine(m.Value.Trim());
}

// output:
// 2
// border-style:solid
// border-width:thin

#DTEST
{
	border-style   
	:  solid      ;
	border-width        :  thin          ;
	position:relative;
	right:10px;
	left:900px;
	width:50px;
}

 but it works only if the css rule contains only one attribute like this:
 .Red
{
    color:Blue;	
}