CSS not being applied in my blank ASP.Net MVC App-Collection of common programming errors

Using Visual Studio, I created a blank ASP.Net MVC 2 app. I added a Site.Master page to the Views\Shared folder. I edited the Site.css file in the Content folder to apply some styles. But at runtime the styles don’t apply. I then edited the Site.Master file to include a section within the section. Within this section I pasted in the content of my Site.css file. Then the styles show perfectly at runtime. But if I replace the section with a instead, then the styles do not show at runtime. Any advice as to what I’m missing?