I want the background color of the tab panel to be a light blue. In addition, the background color of the tab should probably be light blue.

I think I need to apply a theme to it. I've found a couple examples but whenever I try it seems to lose all css styles applied to it.

Here, I set the CssClass property for the TabContainer.
Code:
<cc1:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="0" CssClass="ajax__tab_custom_theme">
Here, I include the css file with my custom theme.
Code:
<head runat="server">
    <title>Untitled Page</title>
    <link href="customtab.css" rel="stylesheet" type="text/css" />
</head>
Here is my css file
Code:
body
{
    font-family:verdana,tahoma,helvetica;
}

/* ajax__tab_custom_theme theme */
.ajax__tab_custom_theme .ajax__tab_header 
{
    font-family:verdana,tahoma,helvetica;
    font-size:11px;
    background:url(img/xp/tab-line.gif) repeat-x bottom;
}
.ajax__tab_custom_theme .ajax__tab_header .ajax__tab_outer 
{
    padding-right:4px;
    background:url(img/xp/tab-right.gif) no-repeat right;
    height:21px;
}
.ajax__tab_custom_theme .ajax__tab_header .ajax__tab_inner 
{
    padding-left:3px;
    background:url(img/xp/tab-left.gif) no-repeat;
}
.ajax__tab_custom_theme .ajax__tab_header .ajax__tab_tab
{
    height:13px;
    padding:4px;
    margin:0;
    background:url(img/xp/tab.gif) repeat-x;
}
.ajax__tab_custom_theme .ajax__tab_hover .ajax__tab_outer 
{
    background:url(img/xp/tab-hover-right.gif) no-repeat right;
}
.ajax__tab_custom_theme .ajax__tab_hover .ajax__tab_inner 
{
    background:url(img/xp/tab-hover-left.gif) no-repeat;
}
.ajax__tab_custom_theme .ajax__tab_hover .ajax__tab_tab 
{
    background:url(img/xp/tab-hover.gif) repeat-x;
}
.ajax__tab_custom_theme .ajax__tab_active .ajax__tab_outer 
{
    background:url(img/xp/tab-active-right.gif) no-repeat right;
}
.ajax__tab_custom_theme .ajax__tab_active .ajax__tab_inner 
{
    background:url(img/xp/tab-active-left.gif) no-repeat;
}
.ajax__tab_custom_theme .ajax__tab_active .ajax__tab_tab 
{
    background:url(img/xp/tab-active.gif) repeat-x;
}
.ajax__tab_custom_theme .ajax__tab_body 
{
    font-family:verdana,tahoma,helvetica;
    font-size:10pt;
    border:1px solid #999999;
    border-top:0;
    padding:8px;
    background-color:#ffffff;
}
Can someone help?

Thanks,