Here is an example of the html of a notification email. As you can see, it has a bunch of text-align: center; tags. Where do these come from?
<style scoped="scoped" type="text/css"><!--
body.hikashop_mail{background-color:#ffffff;color:#575757;}.ReadMsgBody{width:100%;}.ExternalClass{width:100%;}div,p,a,li,td{-webkit-text-size-adjust:none;}@media (min-width:600px){#hikashop_mail{width:600px!important;margin:auto!important;}.pict img{max-width:500px!important;height:auto!important;}}@media (max-width:330px){#hikashop_mail{width:300px!important;margin:auto!important;}table[class=w600],td[class=w600],table[class=w598],td[class=w598],table[class=w500],td[class=w500],img[class="w600"]{width:100%!important;}td[class="w49"]{width:10px!important;}.pict img{max-width:278px;height:auto!important;}}@media (min-width:331px) and (max-width:480px){#hikashop_mail{width:450px!important;margin:auto!important;}table[class=w600],td[class=w600],table[class=w598],td[class=w598],table[class=w500],td[class=w500],img[class="w600"]{width:100%!important;}td[class="w49"]{width:20px!important;}.pict img{max-width:408px;height:auto!important;}}h1{color:#1c8faf;font-size:16px;font-weight:bold;border-bottom:1px solid #ddd;padding-bottom:10px;}h2{color:#89a9c1;font-size:14px;font-weight:bold;margin-top:20px;margin-bottom:5px;border-bottom:1px solid #d6d6d6;padding-bottom:4px;}a:visited{cursor:pointer;color:#2d9cbb;text-decoration:none;border:none;}
--></style>
<div id="hikashop_mail" style="font-family: Arial, Helvetica,sans-serif; font-size: 12px; line-height: 18px; width: 100%; background-color: #ffffff; padding-bottom: 20px; color: #5b5b5b;">
<div class="hikashop_online" style="font-family: Arial, Helvetica,sans-serif; font-size: 11px; line-height: 18px; color: #6a5c6b; text-decoration: none; margin: 10px; text-align: center;"><a style="cursor: pointer; color: #2d9cbb; text-decoration: none; border: none;" href="index.php?option=com_hikashop&ctrl=order&task=show&cid[]=78&Itemid=121"> <span class="hikashop_online" style="color: #6a5c6b; text-decoration: none; font-size: 11px; margin-top: 10px; margin-bottom: 10px; text-align: center;"> Si vous ne voyez pas ce message correctement, cliquez ici pour voir le détails de votre commande </span> </a></div>
<table class="w600" style="font-family: Arial, Helvetica, sans-serif; font-size: 12px; line-height: 18px; margin: auto; background-color: #ebebeb; text-align: center; width: 600px;" border="0" cellspacing="0" cellpadding="0">
<tbody>
<tr style="line-height: 0px;">
<td class="w600" style="line-height: 0px;" width="600" valign="bottom"><img class="w600" src="media/com_hikashop/images/mail/header.png" border="0" alt="" /></td>
</tr>
<tr>
<td class="w600" style="text-align: center;" width="600">
<table class="w600" border="0" cellspacing="0" cellpadding="0" style="margin: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 12px; line-height: 18px; width: 600px;">
<tbody>
<tr>
<td class="w20" width="20"> </td>
<td class="w560 pict" style="text-align: left; color: #575757;" width="560">
<div id="title" style="font-family: Arial, Helvetica, sans-serif; font-size: 12px; line-height: 18px;"><img src="/media/com_hikashop/images/icons/icon-48-order.png" border="0" alt="" style="float: left; margin-right: 4px;" />
<h1 style="color: #1c8faf !important; font-size: 16px; font-weight: bold; border-bottom: 1px solid #ddd; padding-bottom: 10px;">Votre commande</h1>
<h2 style="color: #1c8faf !important; font-size: 12px; font-weight: bold; padding-bottom: 10px;">Votre commande No. <a href="index.php?option=com_hikashop&ctrl=order&task=show&cid[]=78&Itemid=121">D7K8</a> est maintenant confirmée.</h2>
</div>
</td>
<td class="w20" width="20"> </td>
</tr>
<tr>
<td class="w20" width="20"> </td>
<td style="border: 1px solid #adadad; background-color: #ffffff;">
<div class="w550" width="550" id="content" style="font-family: Arial, Helvetica, sans-serif; font-size: 12px; line-height: 18px; margin-left: 5px; margin-right: 5px;">
<p> </p>
<h3 style="color: #393939 !important; font-size: 14px; font-weight: bold; margin-bottom: 0px; padding: 0px;">Bonjour Mothe,</h3>
Merci pour votre commande sur http://www.catholicsforisrael.com/.
<p> </p>
<table class="w550" border="0" cellspacing="0" cellpadding="0" style="margin-top: 10px; font-family: Arial, Helvetica, sans-serif; font-size: 12px; line-height: 18px; width: 550px;">
<tbody>
<tr>
<td style="color: #1c8faf !important; font-size: 12px; font-weight: bold;">Adresse de facturation</td>
</tr>
<tr>
<td>Téléphone:</td>
</tr>
</tbody>
</table>
<h1 style="color: #1c8faf !important; font-size: 16px; font-weight: bold; border-bottom: 1px solid #ddd; padding-top: 10px; padding-bottom: 10px;">DETAIL DE VOTRE COMMANDE</h1>
<table class="w550" border="0" cellspacing="0" cellpadding="0" style="margin-top: 10px; margin-bottom: 10px; font-family: Arial, Helvetica, sans-serif; font-size: 12px; line-height: 18px; width: 550px;">
<tbody>
<tr>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: left; color: #1c8faf !important; font-size: 12px; font-weight: bold;">Nom</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right; color: #1c8faf !important; font-size: 12px; font-weight: bold;">Prix à l'unité</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right; color: #1c8faf !important; font-size: 12px; font-weight: bold;">Qté</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right; color: #1c8faf !important; font-size: 12px; font-weight: bold;">Total</td>
</tr>
<tr>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px;"><img src="media/com_hikashop/upload/thumbnails/50x50fsO/b14.jpg" alt="" style="float: left; margin-top: 3px; margin-bottom: 3px; margin-right: 6px;" />
<p>FB14 - Le baptême : Notre entrée dans la vie éternelle</p>
<p><a href="index.php?option=com_hikashop&ctrl=order&task=download&file_id=2266&order_id=78&Itemid=121">fb14-bapteme</a></p>
</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">1</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
</tr>
<tr>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px;"><img src="media/com_hikashop/upload/thumbnails/50x50fsO/b15.jpg" alt="" style="float: left; margin-top: 3px; margin-bottom: 3px; margin-right: 6px;" />
<p>FB15 - La confirmation : L'effusion du Saint Esprit</p>
<p><a href="index.php?option=com_hikashop&ctrl=order&task=download&file_id=2268&order_id=78&Itemid=121">fb15-confirmation</a></p>
</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">1</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
</tr>
<tr>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px;"><img src="media/com_hikashop/upload/thumbnails/50x50fsO/b21.jpg" alt="" style="float: left; margin-top: 3px; margin-bottom: 3px; margin-right: 6px;" />
<p>FB21 - Le plan de Dieu pour le mariage et la famille (1) : l'amour humain dans la révélation divine</p>
<p><a href="index.php?option=com_hikashop&ctrl=order&task=download&file_id=2280&order_id=78&Itemid=121">fb21-amour_humain_dans_le_plan_divin</a></p>
</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">1</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
</tr>
<tr>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px;"><img src="media/com_hikashop/upload/thumbnails/50x50fsO/b22.jpg" alt="" style="float: left; margin-top: 3px; margin-bottom: 3px; margin-right: 6px;" />
<p>FB22 - Le plan de Dieu pour le mariage et la famille (2) : le sacrement de mariage</p>
<p><a href="index.php?option=com_hikashop&ctrl=order&task=download&file_id=2282&order_id=78&Itemid=121">fb22-le_mariage</a></p>
</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">1</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
</tr>
<tr>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px;"><img src="media/com_hikashop/upload/thumbnails/50x50fsO/b23.jpg" alt="" style="float: left; margin-top: 3px; margin-bottom: 3px; margin-right: 6px;" />
<p>FB23 - La plan de Dieu pour le mariage et la famille (3) : Le rôle de la famille chrétienne</p>
<p><a href="index.php?option=com_hikashop&ctrl=order&task=download&file_id=2284&order_id=78&Itemid=121">fb23-la_famille_chretienne</a></p>
</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">1</td>
<td style="border-bottom: 1px solid #ddd; padding-bottom: 3px; text-align: right;">$8.90</td>
</tr>
<tr>
<td colspan="3" style="text-align: right; color: #1c8faf !important; font-size: 12px; font-weight: bold;">Sous total</td>
<td style="text-align: right;">$44.50</td>
</tr>
<tr>
<td colspan="3" style="text-align: right; color: #1c8faf !important; font-size: 12px; font-weight: bold;">Coupon</td>
<td style="text-align: right;">$-11.13</td>
</tr>
<tr>
<td colspan="3" style="text-align: right; color: #1c8faf !important; font-size: 12px; font-weight: bold;">Total</td>
<td style="text-align: right;">$33.38</td>
</tr>
</tbody>
</table>
<p><span style="color: #1c8faf !important; font-size: 12px; font-weight: bold;">Mode de paiement :</span> PayPal</p>
<p>A nouveau, merci pour votre commande sur http://www.catholicsforisrael.com/. Nous espérons vous revoir bientôt.<br />Cordialement,<br />Catholics for Israel</p>
</div>
</td>
<td class="w20" width="20"> </td>
</tr>
</tbody>
</table>
</td>
</tr>
<tr style="line-height: 0px;">
<td class="w600" style="line-height: 0px;" width="600" valign="top"><img class="w600" src="media/com_hikashop/images/mail/footer.png" border="0" alt="--" /></td>
</tr>
</tbody>
</table>
</div>