Send RadGrid as quotation to the Gmail

Send RadGrid as quotation to the Gmail

i have created a web page and send this page by email on Gmail. and on
gmail it doesn't pick up any css classes there. but when i send this email
on yahoo or any other professional email it is working very fine.
i am using the css class as below
.tb_head
{
background-color: #da2526;
border: 1px solid #71250a;
border-top: 0;
color: #fff;
text-align: left;
padding: 5px 8px;
}
<HeaderStyle CssClass="tb_head" />
<ItemStyle CssClass="tb_cell" />
these class are embedded inside the page.
and it render on the gmail as
<th scope="col">Location</th>
same is the case for the table rows...
So any help please?