TransparentBox is just the class name. Here's the container and it's css file. It will probably be more helpful that if I try to explain. Let me know if you need additional info.
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My container (TransparentBox.ascx)...........
<%@ Control language="vb" CodeBehind="~/admin/Containers/container.vb" AutoEventWireup="false" Explicit="True" Inherits="DotNetNuke.UI.Containers.Container" %>
<%@ Register TagPrefix="dnn" TagName="SOLPARTACTIONS" Src="~/Admin/Containers/SolPartActions.ascx" %>
<%@ Register TagPrefix="dnn" TagName="TITLE" Src="~/Admin/Containers/Title.ascx" %>
<%@ Register TagPrefix="dnn" TagName="ACTIONBUTTON1" Src="~/Admin/Containers/ActionButton.ascx" %>
<%@ Register TagPrefix="dnn" TagName="ACTIONBUTTON2" Src="~/Admin/Containers/ActionButton.ascx" %>
<%@ Register TagPrefix="dnn" TagName="ACTIONBUTTON3" Src="~/Admin/Containers/ActionButton.ascx" %>
<%@ Register TagPrefix="dnn" TagName="ACTIONBUTTON4" Src="~/Admin/Containers/ActionButton.ascx" %>
<table id="TransparentBox" class="TransparentBox" align=center width="95%" border="0" cellspacing="4" cellpadding="0">
<tr>
<td>
<table width="100%" border="0" cellspacing="1" cellpadding="5">
<tr>
<td>
<table width="100%" border="0" cellspacing="3" cellpadding="0">
<tr>
<td valign="middle" nowrap><dnn:SOLPARTACTIONS runat="server" id="dnnSOLPARTACTIONS"/></td>
<td width="100%" valign="middle" nowrap><dnn:TITLE runat="server" id="dnnTITLE" CssClass="Title"/></td>
</tr valign="top">
<tr>
<hr>
</tr>
<tr valign="top">
<td id="ContentPane" runat="server" align="left" style="padding: 5px" colspan=2></td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
</table>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td height="0">
<table width="100%" height="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td valign="middle" style="padding-left: 5px; padding-right: 5px;" nowrap><dnn:ACTIONBUTTON1 runat="server" id="dnnACTIONBUTTON1" CommandName="AddContent.Action" DisplayIcon="True" DisplayLink="True" /></td>
<td width="100%" valign="middle" style="padding-right: 5px;" nowrap><dnn:ACTIONBUTTON4 runat="server" id="dnnACTIONBUTTON4" CommandName="ModuleSettings.Action" DisplayIcon="True" DisplayLink="False" /></td>
<td valign="middle" style="padding-right: 5px;" nowrap><dnn:ACTIONBUTTON2 runat="server" id="dnnACTIONBUTTON2" CommandName="SyndicateModule.Action" DisplayIcon="True" DisplayLink="False" /></td>
<td valign="middle" style="padding-right: 5px;" nowrap><dnn:ACTIONBUTTON3 runat="server" id="dnnACTIONBUTTON3" CommandName="PrintModule.Action" DisplayIcon="True" DisplayLink="False" /></td>
</tr>
</table>
</td>
</tr>
</table>
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Container.css...........
#TransparentBox .Title
{
font-weight: normal;
font-size: 20px;
color: #FFFFFF;
font-family: Georgia, Arial;
font-style: italic;
}
#TransparentBox .Head
{
color: #FFFFFF;
}
#TransparentBox .SubHead
{
color: #FFFFFF;
}
#TransparentBox .SubSubHead
{
color: #FFFFFF;
}
#TransparentBox .Normal
{
color: #FFFFFF;
}
#TransparentBox .NormalTextBox
{
}
#TransparentBox .NormalRed
{
}
#TransparentBox .NormalBold
{
}
#TransparentBox .CommandButton
{
}
#TransparentBox A.Normal
{
font-weight: bold;
font-size: 11px;
font-family: tahoma;
}
#TransparentBox A.Normal:link
{
color: #C40000;
text-decoration: none;
}
#TransparentBox A.Normal:visited
{
color: #C40000;
text-decoration: none;
}
#TransparentBox A.Normal:active
{
color: #C40000;
text-decoration: none;
}
#TransparentBox A.Normal:hover
{
color: #FFCC00;
text-decoration: underline;
}
#TransparentBox TD {
color: #FFFFFF;
}
#TransparentBox TR {
color: #FFFFFF;
}