CSS not working when am trying to use update panel in my webpage?
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i have webpages with master page which contain my css...When i add update panel in content palce holder, css on master page are working fine but same css not working in content page holder.


    <%@ Page Title="District Master" Language="C#" MasterPageFile="~/webpages/MasterPage_new.master"
        AutoEventWireup="true" CodeFile="frmDistrict.aspx.cs" Inherits="webpages_frmDistrict" %>
    
    <%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
    <asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
        <asp:ScriptManager ID="ScriptManager2" EnablePartialRendering="true" runat="server">
        </asp:ScriptManager>
        <div id="main_div">
            <asp:UpdatePanel ID="uppnl" runat="server" Mode="Conditional">
                <ContentTemplate>
                    <table style="width: 100%; float: left;">
                        <tr>
                            <td style="height: 100px; width: 100%; float: left;">
                                <asp:TextBox ID="txtSearch" runat="server"></asp:TextBox>
                                <asp:Button ID="btnSearchOK" runat="server" Text="Ok" Font-Names="Verdana" Font-Size="11px"
                                    Width="6%" Font-Bold="True" OnClick="btnSearchOK_OnClick" />
                                <asp:Button ID="btnRefresh" runat="server" Text="Refresh" Font-Names="Verdana" Font-Size="11px"
                                    Width="11%" Font-Bold="True" OnClick="btnRefresh_OnClick" />
                                <asp:Button ID="btnClose" runat="server" Text="Close" Font-Names="Verdana" Font-Size="11px"
                                    Width="9%" Font-Bold="True" OnClick="btnClose_OnClick" />
                            </td>
                        </tr>
                    </table>
                </ContentTemplate>
            </asp:UpdatePanel>
        </div>
    </asp:Content>