Did research on this, quickest way to implement a separate stylesheet for content page is to add an extra content placeholder in the head section of the master page. Then for each content page can set a link to the stylesheet. Note that the head section of the master page must be set to runat server. So master page has the following head section:
<head runat="server">
<title>Master Page</title>
<asp:ContentPlaceHolder runat="server" ID="cphHeadSection">
</asp:ContentPlaceHolder>
</head>
Add the following to your content page:
<asp:Content ID="ContentHead" ContentPlaceHolderID="cphHeadSection" runat="server">
<link href="ContentStyles.css" rel="Stylesheet" type="text/css" />
</asp:Content>
ASP.NET
Stylesheet, Content Page, ASP.NET