app/views/layouts/hdo_mail.html.erb
<!DOCTYPE html>
<html style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;">
<head>
<meta name="viewport" content="width=device-width">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title><%= @subject %></title>
</head>
<body bgcolor="#f6f6f6" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; -webkit-font-smoothing: antialiased; height: 100%; -webkit-text-size-adjust: none; width: 100% !important; margin: 0; padding: 0;">
<!-- body -->
<table class="body-wrap" bgcolor="#f6f6f6" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; width: 100%; margin: 0; padding: 20px;">
<tr style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;">
<td style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;"></td>
<td class="container" bgcolor="#FFFFFF" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; clear: both !important; display: block !important; max-width: 600px !important; margin: 0 auto; padding: 20px; border: 1px solid #f0f0f0;">
<!-- content -->
<div class="content" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; display: block; max-width: 600px; margin: 0 auto; padding: 0;">
<table style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; width: 100%; margin: 0; padding: 0;">
<tr style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;">
<td style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;">
<%= yield %>
</td>
</tr>
</table>
</div>
<!-- /content -->
</td>
<td style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;"></td>
</tr>
</table>
<!-- /body -->
<!-- footer -->
<table class="footer-wrap" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; clear: both !important; width: 100%; margin: 0; padding: 0;">
<tr style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;">
<td style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;"></td>
<td class="container" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; clear: both !important; display: block !important; max-width: 600px !important; margin: 0 auto; padding: 0;">
<!-- content -->
<div class="content" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; display: block; max-width: 600px; margin: 0 auto; padding: 0;">
<table style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; width: 100%; margin: 0; padding: 0;">
<tr style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;">
<td align="center" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;">
<p style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 12px; line-height: 1.6em; color: #666666; font-weight: normal; margin: 0 0 10px; padding: 0;">
<a href="mailto:kontakt@holderdeord.no" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; color: #999999; margin: 0; padding: 0;">kontakt@holderdeord.no
</p>
</td>
</tr>
</table>
</div>
<!-- /content -->
</td>
<td style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; font-size: 100%; line-height: 1.6em; margin: 0; padding: 0;"></td>
</tr>
</table>
<!-- /footer -->
</body>
</html>