using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string input = "My name is Jason <and maybe> I just seem like <a kid> but I not";

        string regexPattern = "(<)([^<>]*)(>)";

        string output = Regex.Replace(input, regexPattern, m => "<span style='color:red'>" + m.Groups[2].Value + "</span>");

        Console.WriteLine(output);

    }

}