problems with css and javascript in ASP.NET

Hi to all,
I'm learning ASP.NET (I know pretty good HTML, CSS, JavaScript and PHP from earlier) and I have a few problems with CSS and JavaScript.
I have a project called WebSite5 and a page cback.aspx in it.
I put a code for external css file in  <head> of cback.aspx:
...

<link rel="Stylesheet" type="text/css" name="style.css" />
</head>
I wrote style.css file with following code:
div {
background-color:#6699FF;
}
In cback.aspx, I have element <div>. Part of code:
---------------------------------------------

<body>
    <form id="form1" runat="server">
    <div>
    <asp:label id="lblLoadTime" runat="server">
</asp:label><br /><br />
<asp:label id="lblMessage" runat=" ...