The Cell Padding (as seen in the first table) disappears when viewed in Mozilla Thunderbird and some outlook versions and as a result the rest of the content is no longer aligned properly in the center (shifts left)..... Any help or advice as to what I may be doing wrong is appreciated!

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                                    <table width="640" border="0" cellspacing="0" cellpadding="20" class="100p">
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                                                        <td align="left" width="50%" class="100p"><img src="https://gallery.mailchimp.com/d82dce6e8620e55e42c5cae84/images/b3ac5acd-bb81-4dea-98d7-a5dd9085e9ec.png" alt="Logo" border="0" style="display:block" /></td>
                                                        <td width="50%" class="hide" align="right" style="font-size:14px; color:#FFFFFF;"><font face="'Roboto', Arial, sans-serif"><a href="#" style="color:#FFFFFF; text-decoration:none;">OFFICE</a>  &nbsp;  | &nbsp;  <a href="#" style="color:#FFFFFF; text-decoration:none;">ANTIVIRUS</a>  &nbsp; | &nbsp;  <a href="#" style="color:#FFFFFF; text-decoration:none;">HOT DEALS</a></font></td>
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                                                                <span style="font-size:44px;">Welcome to ITF</span><br />
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                                                                <Span style="font-size:24px;">Canada's online store<br>for software and tech accessories</Span>
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                                                                <table border="0" cellspacing="0" cellpadding="10" style="border:2px solid #FFFFFF;">
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                                                                        <td align="center" style="color:#FFFFFF; font-size:16px;"><font face="'Roboto', Arial, sans-serif"><a href="##" style="color:#FFFFFF; text-decoration:none;">START SHOPPING</a></font></td>
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