http://msmvps.com/blogs/laflour/archive/2008/05/15/css-and-asp-net-menu-in-sharepoint.aspxUsing CSS in SharePoint differs a little bit from the standard approach we use in ASP.NET applications - some styles doesn't work as they expected to work. The major problem is that SharePoint doesn't understand some CSS applied on ASP.NET сontrolsenCommunityServer 2008.5 SP2 (Build: 40407.4157)