GridViewHyperLinkField.aspx font size:
C# source: GridViewHyperLinkField.aspx   title_details.aspx   
View Sample
<html>
<head>
<title>GridView HyperLinkField Example</title>
<link rel="stylesheet" href="/shared/netdemos.css">
</head>

<body>
<!-- #include virtual="~/shared/top.inc" -->
<div class="header"><h2>GridView <span class="hilite">HyperLinkField</span> Example</h2></div>
<hr size=1 width=92%>

<div align="center">
<form runat="server">
   <asp:gridview id="titlesGrid" runat="server"
      datasourceid="titles"
      width=90% cellpadding=5 font-size="9pt"
      autogeneratecolumns=false
      headerstyle-backcolor="maroon"
      headerstyle-forecolor="khaki"
      headerstyle-font-bold
      rowstyle-verticalalign="top">

      <columns>
         <asp:hyperlinkfield headertext="Title"
            datatextfield="title"
            datanavigateurlformatstring="title_details.aspx?titleid={0}"
            datanavigateurlfields="title_id" />
         <asp:boundfield headertext="Title ID"
            datafield="title_id" />
         <asp:boundfield headertext="Category"
            datafield="type" />
         <asp:boundfield headertext="Pub ID"
            datafield="pub_id" />
         <asp:boundfield headertext="Price"
            datafield="price"
            htmlencode=false
            dataformatstring="{0:n2}"
            itemstyle-horizontalalign="right" />
      </columns>

   </asp:gridview>
 
   <asp:sqldatasource id="titles" runat="server"
      selectcommand="SELECT * FROM Titles"
      datasourcemode="datareader"
      connectionstring="<%$ ConnectionStrings:aspnet %>" />

</form>
</div>

<hr size=1 width=92%>
<!-- #include virtual="~/shared/viewsrc.inc" -->

</body>
</html>