<location path="Form.css">
    <system.web>
      <authorization>
        <allow users="*"/>
      </authorization>
    </system.web>
  </location>

<authentication mode="Forms">
      <forms name ="WebApp.ASPXAUTH"
            loginUrl="login.aspx"
             protection="All"
             path ="/"/>
    </authentication>
    <authorization>
      <allow users ="*"/>
    </authorization>

<link rel="stylesheet" src="path of the stylesheet" type="text/css">