Как отправить HTML/CSS письмо на электронную почту?

public static void SendMail(string address, string subject, string body, System.Text.Encoding encoding = null, Dictionary<string, byte[]> attachments = null)
        {
            if (null == encoding) encoding = System.Text.Encoding.Default;
            SmtpClient client = new SmtpClient()
            {
                Port = SmtpSettings.Network.Port,
                DeliveryMethod = SmtpDeliveryMethod.Network,
                UseDefaultCredentials = false,
                Host = SmtpSettings.Network.Host,
                EnableSsl = false,
                Credentials = new System.Net.NetworkCredential(SmtpSettings.Network.UserName, SmtpSettings.Network.Password)
            };
            byte[] bodyEnc = System.Text.Encoding.UTF8.GetBytes(body);
            byte[] encoded = System.Text.Encoding.Convert(System.Text.Encoding.UTF8, encoding, bodyEnc);
            string encodedbody = encoding.GetString(encoded);

            MailMessage mail = new MailMessage(
                new MailAddress(SmtpSettings.From, "Имя отправителя", encoding),
                new MailAddress(address, "Имя получателя", encoding)
                )
            {
                Subject = subject,
                Body = body,
                IsBodyHtml = true
            };

            if (attachments != null && attachments.Count != 0)
            {
                foreach (var kvp in attachments)
                {
                    using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
                    {
                        ms.Write(kvp.Value, 0, kvp.Value.Length);
                        mail.Attachments.Add(new Attachment(ms, kvp.Key));
                    } // using
                } // foreach
            }
            try
            {
                client.Send(mail);
            }
            catch(Exception ex)
            {
                 // TODO: Handle Send fail
            }
        }