ASP.net Create Styles

The following link shows adding the style below. Where exactly does the style code
below go. I tried just pasting it at the bottom of Site.css and it didn't work

http://www.codeproject.com/Articles/313197/Simple-way-to-Design-Tabs-in-ASP-NET

 <style type="text/css">
  .Initial
  {
    display: block;
    padding: 4px 18px 4px 18px;
    float: left;
    background: url("../Images/InitialImage.png") no-repeat right top;
    color: Black;
    font-weight: bold;
  }
  .Initial:hover
  {
    color: White;
    background: url("../Images/SelectedButton.png") no-repeat right top;
  }
  .Clicked
  {
    float: left;
    display: block;
    background: url("../Images/SelectedButton.png") no-repeat right top;
    padding: 4px 18px 4px 18px;
    color: Black;
    font-weight: bold;
    color: White;
  }
  </style>