Align GridView in center of page in ASP.Net

Gridview alignment in row is not coming in center 

https://ibb.co/G5vS1Hc

<%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="impinv.aspx.cs" Inherits="Hecotex.impinv" %>

<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.min.css" />
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.min.js"></script>
    <script type="text/javascript">
        $(function () {
            $(".js-example-placeholder-single").select2({
                placeholder: "Select",
                allowClear: true
            });
        });
        </script>
    <style>
        .auto-style1 {
            text-align: right;
            width: 722px;
            height: 48px;
        }

        .auto-style2 {
            width: 459px;
        }

        .auto-style3 {
            text-align: right;
            width: 241px;
            height: 48px;
        }

        .auto-style4 {
            width: 834px;
        }

        .auto-style5 {
            text-align: right;
            width: 722px;
        }

        .auto-style6 {
            text-align: right;
            width: 241px;
        }
    </style>
    <div>
        <table class="auto-style1">
            <tr>
                <td class="auto-style3" colspan="4">
                    <h1 class="auto-style34">Import Invoice</h1>
                </td>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px; height: 42px">&nbsp;ID :</td>
                <td class="auto-style32" style="width: 459px; height: 42px;">&nbsp;<asp:TextBox ID="cno" Enabled="false" runat="server" Width="90px" Height="25px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
                </td>
                <td class="text-right" style="width: 241px; height: 42px;">Date :</td>
                <td class="auto-style20" style="width: 834px; height: 42px;">
                    <asp:TextBox ID="txtdt" runat="server" Width="122px" Height="25px"></asp:TextBox>
            </tr>
            <tr>
                <td class="auto-style5">Invoice No :</td>
                <td class="auto-style2">&nbsp;<asp:TextBox ID="txtino" runat="server" Width="150px" Height="25px" Style="text-align: left" OnTextChanged="txtino_TextChanged"></asp:TextBox>
                </td>
                <td class="auto-style6">Category :</td>
                <td class="auto-style4">
                    <asp:DropDownList ID="DDLCAT" CssClass="form-control js-example-placeholder-single"
                        ToolTip="Select Category " Height="16px" runat="server">
                    </asp:DropDownList>
                    &nbsp;</td>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px; height: 44px">Location :</td>
                <td class="auto-style12" style="width: 459px; height: 44px;">

                    <asp:DropDownList CssClass="form-control js-example-placeholder-single"
                        ToolTip="Select Location " Height="16px" ID="ddlloc" runat="server" Style="margin-left: 29">
                    </asp:DropDownList>
                </td>
                <td class="text-right" style="width: 241px; height: 44px;">Supplier :</td>
                <td class="auto-style18" style="width: 834px; height: 44px;">
                    <asp:DropDownList ID="ddlsup" CssClass="form-control js-example-placeholder-single"
                        ToolTip="Select Category " Height="16px" runat="server">
                    </asp:DropDownList>
                </td>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px; height: 36px">Container: </td>
                <td class="auto-style12" style="width: 459px; height: 36px;">
                    <asp:TextBox ID="txtcont" runat="server" Width="150px" Height="25px"></asp:TextBox>
                </td>
                <td class="text-right" style="width: 241px; height: 36px;">Clearing Agent:
                </td>
                <td class="auto-style18" style="width: 834px; height: 36px;">
                    <div class="text-left">
                        <asp:DropDownList ID="DDLAg" CssClass="form-control js-example-placeholder-single"
                            ToolTip="Select Agent " Height="16px" runat="server">
                        </asp:DropDownList>
                    </div>
                </td>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px; height: 35px">Forwarder :</td>
                <td class="auto-style12" style="width: 459px; height: 35px;">
                    <asp:DropDownList CssClass="form-control js-example-placeholder-single"
                        ToolTip="Select " Height="16px" ID="DDLFw" runat="server">
                    </asp:DropDownList>
                </td>
                <td class="text-right" style="width: 241px; height: 35px;">Good Type :
                </td>
                <td class="auto-style18" style="width: 834px; height: 35px;">
                    <asp:DropDownList ID="ddltype" CssClass="form-control js-example-placeholder-single"
                        ToolTip="Select Category " Height="16px" Width="95px" runat="server">
                        <asp:ListItem Text="Select" Value="0" />
                        <asp:ListItem Text="A" Value="1" />
                        <asp:ListItem Text="B" Value="2" />
                    </asp:DropDownList>
                </td>
            </tr>
            <tr>
                <td class="text-right" style="height: 20px; width: 722px"></td>
                <td class="auto-style12" style="width: 459px; height: 20px;"></td>
                <td class="text-right" style="width: 241px; height: 20px;"></td>
                <td class="auto-style18" style="width: 834px; height: 20px;"></td>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px; height: 20px;">Freight Ref. :</td>
                <td class="auto-style12" style="width: 459px; height: 20px;">
                    <asp:TextBox ID="txtfrghtrt" runat="server" Width="150px" Height="25px"></asp:TextBox>
                </td>
                <td class="text-right" style="width: 241px; height: 20px;">Port:</td>
                <td class="auto-style18" style="width: 834px; height: 20px;">
                    <asp:DropDownList ID="ddlport" CssClass="form-control js-example-placeholder-single"
                        ToolTip="Select Port " Height="16px" runat="server">
                    </asp:DropDownList>
                </td>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px">
                    <br />
                </td>
                <td class="auto-style12" style="width: 459px">&nbsp;&nbsp;&nbsp;
                </td>
                <td class="text-right" style="width: 241px">&nbsp;</td>
                <td class="auto-style18" style="width: 834px">&nbsp;</td>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px; height: 43px">F Amt :</td>
                <td class="auto-style15" style="width: 459px; height: 43px;">
                    <asp:TextBox ID="txtfrghtrt0" runat="server" Width="122px" Height="25px"></asp:TextBox>
                </td>
                <td class="text-right" style="width: 241px; height: 43px;">Internal Inv # </td>
                <td class="auto-style17" style="width: 834px; height: 43px;">

                    <asp:TextBox ID="txtintinv" runat="server" Width="150px" Height="25px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp; Booking :

                    <asp:TextBox ID="txtboking" runat="server" Width="80px" Height="25px"></asp:TextBox>
            </tr>
            <tr>
                <td class="text-right" style="width: 722px; height: 38px">&nbsp;</td>
                <td class="auto-style12" style="width: 459px; height: 38px;">&nbsp;</td>
                <td class="auto-style19" style="width: 241px; height: 38px;"></td>
                <td class="auto-style18" style="width: 834px; height: 38px;"></td>
            </tr>
            <tr>
                <td class="auto-style7" style="width: 722px">&nbsp;</td>
                <td class="auto-style12" style="width: 459px">
                    <asp:Button ID="btn_sv" runat="server" Text="Save" Width="54px" OnClick="btn_sv_Click" />
                    <asp:Button ID="btn_updt" runat="server" Text="Update" OnClick="Update_Click" />
                    <asp:Button ID="btn_del" runat="server" Text="Delete" OnClick="Delete_Click" />
                </td>
                <td class="auto-style19" style="width: 241px">&nbsp;</td>
                <td class="auto-style18" style="width: 834px">&nbsp;</td>
            </tr>
            <tr>
                <td class="auto-style22" style="width: 722px"></td>
                <td class="auto-style23" style="width: 459px"></td>
                <td class="auto-style24" style="width: 241px"></td>
                <td class="auto-style25" style="width: 834px"></td>
            </tr>
            <tr>
                <td class="auto-style10" colspan="4">&nbsp;&nbsp;<span class="auto-style30">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;</span><span class="auto-style27"> </span><span class="auto-style26"><strong><span class="auto-style27">Description</span></strong></span><span class="auto-style27">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; </span><span class="auto-style26"><strong><span class="auto-style27">QTY</span></strong></span><span class="auto-style27">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span class="auto-style26"><strong><span class="auto-style27">Rate</span></strong></span> <strong><span class="auto-style29">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </span><span class="auto-style28">&nbsp;Transport</span></strong><span class="auto-style27">&nbsp;&nbsp; </span><span class="auto-style26"><strong><span class="auto-style27">Freight</span></strong></span><span class="auto-style27">&nbsp;&nbsp;&nbsp; 
                    </span><span class="auto-style26"><strong><span class="auto-style27">Additional</span></strong></span><span class="auto-style27">&nbsp;&nbsp; </span><span class="auto-style26"><strong><span class="auto-style27">Amount</span></strong></span><span class="auto-style27">&nbsp;&nbsp;&nbsp;&nbsp; </span><span class="auto-style26"><strong><span class="auto-style27">Bales</span></strong></span></td>
            </tr>
            <tr>
                <td class="auto-style18" colspan="4" style="height: 53px">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;
                    &nbsp;<asp:DropDownList ID="ddldesc" CssClass="form-control js-example-placeholder-single"
                    ToolTip="Select Category " Height="16px" runat="server" Width="156px">
                </asp:DropDownList>
                    &nbsp;
                    <asp:TextBox ID="txtqty" runat="server" Height="25px" Width="40px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp;

                    <asp:TextBox ID="txtrt" runat="server" Height="25px" Width="40px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp;
                    <asp:TextBox ID="txttrns" runat="server" Height="25px" Width="40px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                    <asp:TextBox ID="txtfrh" runat="server" Height="25px" Width="40px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;

                    <asp:TextBox ID="txtadditional" runat="server" Height="25px" Width="40px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;
                    <asp:TextBox ID="txtamt" runat="server" Height="25px" Width="40px"></asp:TextBox>
                    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                    <asp:TextBox ID="txtbal" runat="server" Height="25px" Width="40px"></asp:TextBox>


                    &nbsp;
               
              

                    <asp:Button ID="btn_add" runat="server" Text="Add" BackColor="#66CCFF" BorderColor="White" BorderStyle="Double" ForeColor="White" OnClick="btn_add_Click" />
            </tr>
            <tr>
                <td colspan="4">
                    <div class="col-sm-3 pull-center">
                        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
                       
                        <div class="text-center">
                            <asp:GridView ID="GridView1" HorizontalAlign="Center" runat="server" AllowSorting="True" AutoGenerateColumns="false" CssClass="mygrdContent" HeaderStyle-BackColor="#66ccff" HeaderStyle-CssClass="header" HeaderStyle-ForeColor="White" PagerStyle-CssClass="pager" RowStyle-CssClass="rows" EmptyDataText="No Date." Height="81px" ShowHeaderWhenEmpty="True" Width="947px">
                                <Columns>
                                    <%--<asp:BoundField DataField="Prdno" ReadOnly="True" HeaderText="Bale_No" />--%>
                                    <asp:TemplateField HeaderText="Item" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_item" runat="server" Text='<%#Bind("lb_item")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>

                                    <asp:TemplateField HeaderText="Qty" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_qty" runat="server" Text='<%#Bind("lb_qty")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>

                                    <asp:TemplateField HeaderText="Rate" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_rate" runat="server" Text='<%#Bind("lb_rate")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>

                                    <asp:TemplateField HeaderText="Transport" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_transport" runat="server" Text='<%#Bind("lb_transport")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Freight" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_freight" runat="server" Text='<%#Bind("lb_freight")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Additional" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_additional" runat="server" Text='<%#Bind("lb_additional")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Amount" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_amount" runat="server" Text='<%#Bind("lb_amount")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Bales" HeaderStyle-Width="8%" ItemStyle-Width="8%">
                                        <ItemTemplate>
                                            <asp:Label ID="lb_Bale" runat="server" Text='<%#Bind("lb_Bale")%>'></asp:Label>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:CommandField ButtonType="Button" ShowDeleteButton="True" HeaderStyle-Width="8%" ItemStyle-Width="8%" />
                                </Columns>
                                <HeaderStyle BackColor="#66CCFF" ForeColor="White" />
                                <SelectedRowStyle BackColor="Yellow" />
                            </asp:GridView>

                        </div>

                    </div>
                </td>
            </tr>
        </table>
    </div>
</asp:Content>