app/views/mailer/question_deadline.html.erb
<%= render('greeting') %>
<p>
<%= t('mailer.question_deadline.body_html', href: opportunity_url(@opportunity), title: @opportunity.title) %>
</p>
<p class='centered padding'>
<a class='btn-primary' href='<%= opportunity_url(@opportunity) %>'>
<%= t('ask_question') %> →
</a>
</p>