class Program
    {
        static string CompressCSS()
        {
            var css = @"
                a {
                    background: #F9BE4486;
                    color: #FFFFFF20;
                }";
            var compressor = new CssCompressor();
            // The background value is correct.
            // The expected result of color is #FFFFFF20, and the actual result is #FFF20.
            var compressedCSS = compressor.Compress(css); // a{background:#F9BE4486;color:#FFF20}

            return compressedCSS;
        }
    }