Program.cs

using System;

namespace BridgePattern
{
  class Program
  {
    interface IWebPage
    {
      string GetContent();
    }

    class About : IWebPage
    {
      protected ITheme theme;

      public About(ITheme theme)
      {
        this.theme = theme;
      }

      public string GetContent()
      {
        return String.Format("About page in {0}", theme.GetColor());
      }
    }

    class Careers : IWebPage
    {
      protected ITheme theme;

      public Careers(ITheme theme)
      {
        this.theme = theme;
      }

      public string GetContent()
      {
        return String.Format("Careers page in {0}", theme.GetColor());
      }
    }

    interface ITheme
    {
      string GetColor();
    }

    class DarkTheme : ITheme
    {
      public string GetColor()
      {
        return "Dark Black";
      }
    }

    class LightTheme : ITheme
    {
      public string GetColor()
      {
        return "Off White";
      }
    }

    class AquaTheme : ITheme
    {
      public string GetColor()
      {
        return "Light blue";
      }
    }
    static void Main(string[] args)
    {
      var darkTheme = new DarkTheme();

      var about = new About(darkTheme);
      var careers = new Careers(darkTheme);

      Console.WriteLine(about.GetContent());
      Console.WriteLine(careers.GetContent());
      Console.ReadLine();
    }
  }
}