Tweak email CSS for nicer display in dark mode

templates/emails/base.html

@@ -117,7 +117,7 @@
         </td>
     </tr>
     <tr>
-        <td bgcolor="#ffffff" align="center" style="padding: 50px 15px 70px 15px;" class="section-padding">
+        <td align="center" style="padding: 50px 15px 70px 15px;" class="section-padding">
             <!--[if (gte mso 9)|(IE)]>
             <table align="center" border="0" cellspacing="0" cellpadding="0" width="600">
             <tr>
@@ -180,7 +180,7 @@
     </tr>
 
     <tr>
-        <td bgcolor="#ffffff" align="center" style="padding: 20px 0px;">
+        <td align="center" style="padding: 20px 0px;">
             <!--[if (gte mso 9)|(IE)]>
             <table align="center" border="0" cellspacing="0" cellpadding="0" width="600">
             <tr>