openproject/app/views/layouts/mailer.text.html.erb

<html>
<head>
<style>
body {
  font-family: Verdana, sans-serif;
  font-size: 0.8em;
  color:#484848;
}
h1, h2, h3 { font-family: "Trebuchet MS", Verdana, sans-serif; margin: 0px; }
h1 { font-size: 1.2em; }
h2, h3 { font-size: 1.1em; }
a, a:link, a:visited { color: #2A5685;}
a:hover, a:active { color: #c61a1a; }
a.wiki-anchor { display: none; }
hr {
  width: 100%;
  height: 1px;
  background: #ccc;
  border: 0;
}
.footer {
  font-size: 0.8em;
  font-style: italic;
}
</style>
</head>
<body>
<span class="header"><%= Redmine::WikiFormatting.to_html(Setting.text_formatting, Setting.emails_header) %></span>
<%= call_hook(:view_layouts_mailer_html_before_content, self.assigns) %>
<%= yield %>
<%= call_hook(:view_layouts_mailer_html_after_content, self.assigns) %>
<hr />
<span class="footer"><%= Redmine::WikiFormatting.to_html(Setting.text_formatting, Setting.emails_footer) %></span>
</body>
</html>