Print ASP.Net GridView with CSS using ItextSharp

My GridView PDF print does not appear good when I printed it. How do I add margin and padding I order to create some horizontal and vertical space in the cells and make it look good?

GridView: HTML

<asp:GridView ID="GridView1" runat="server" GridLines="None" DataKeyNames="Id" AllowPaging="true" PageSize="10" HeaderStyle-ForeColor="#05214d" HeaderStyle-Font-Size="10pt" Font-Size="10pt"
    AutoGenerateColumns="false" OnRowDataBound="OnRowDataBound" HeaderStyle-HorizontalAlign="left" RowStyle-HorizontalAlign="Left" OnPageIndexChanging="OnPageIndexChanging" HeaderStyle-BackColor="#f5f5f5" RowStyle-BackColor="#fdfdfd" AlternatingRowStyle-BackColor="White" AlternatingRowStyle-ForeColor="#000" class="table" Width="100%">
    <EmptyDataTemplate>
        <div style="text-align: center; font-weight: 500; margin-top: 2%;">
            <i class="fal fa-file-times" style="margin: 0 auto; font-size: 30pt; color: #145c7c;"></i>
            <p id="P1" runat="server" style="font-size: 11pt; font-weight: 400;">No Record</p>
        </div>
    </EmptyDataTemplate>
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:CheckBox ID="check" runat="server" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:BoundField DataField="Id" HeaderText="ID" HeaderStyle-Font-Bold="false" />
        <asp:BoundField DataField="RegName" HeaderText="Name" HeaderStyle-Font-Bold="false" ItemStyle-Font-Size="10pt" />
        <asp:BoundField DataField="phoneNumber" HeaderText="Phone Number" HeaderStyle-Font-Bold="false" ItemStyle-Font-Size="10pt" />
        <asp:BoundField DataField="email" HeaderText="Email" HeaderStyle-Font-Bold="false" ItemStyle-Font-Size="10pt" />
        <asp:BoundField DataField="RegDate" HeaderText="Date Registered" HeaderStyle-Font-Bold="false" ItemStyle-Font-Size="10pt" />
    </Columns>
</asp:GridView>

Printing: C#

protected void ExportToPDF(object sender, EventArgs e)
{
    string fileName = Topic.Text + ".pdf";
    using (StringWriter sw = new StringWriter())
    {
        using (HtmlTextWriter hw = new HtmlTextWriter(sw))
        {
            GridView1.AllowPaging = false;
            this.GetRegistrationDetails();
 
            GridView1.RenderControl(hw);
            StringReader sr = new StringReader(sw.ToString());
            Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
            PdfWriter writer = PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
 
            HtmlPipelineContext htmlContext = new HtmlPipelineContext(null);
            htmlContext.SetTagFactory(Tags.GetHtmlTagProcessorFactory());
            ICSSResolver cssResolver = XMLWorkerHelper.GetInstance().GetDefaultCssResolver(false);
            cssResolver.AddCssFile(Server.MapPath("~/css/style2.css"), true);
            pdfDoc.Open();
            XMLWorkerHelper.GetInstance().ParseXHtml(writer, pdfDoc, sr);
            pdfDoc.Close();
            Response.ContentType = "application/pdf";
            Response.AddHeader("content-disposition", "attachment;filename= " + fileName + ";");
            Response.Cache.SetCacheability(HttpCacheability.NoCache);
            Response.Write(pdfDoc);
            Response.End();
        }
    }
}
public override void VerifyRenderingInServerForm(Control control)
{
    /* Verifies that the control is rendered */
}