title: Implementing Themes for web application
body: <p>I'm building a web application and I would like to have different color themes that user can select. </p>
  
  <p>I can have different stylesheets and then I can load the one that I want but I think this would be a lot of code ( even if I just take out the theme level CSS into a separate file ). </p>
  
  <p>I want to know if there is a way that I can somehow set global theme parameter and then all CSS properties can use it to calculate colors suitable for that theme parameter value.</p>