openproject/app/views/common/_error_base.html.erb

<%#-- copyright
OpenProject is an open source project management software.
Copyright (C) 2012-2021 the OpenProject GmbH

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 3.

OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
Copyright (C) 2006-2013 Jean-Philippe Lang
Copyright (C) 2010-2013 the ChiliProject Team

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

See COPYRIGHT and LICENSE files for more details.

++#%>

<div id="errorExplanation"
     class="notification-box errorExplanation -error <%= local_assigns[:classes] || '' %>"
     tabindex="0"
     role="alert">
  <div class="notification-box--content">
    <% if content_for?(:error_details) %>
      <p>
        <strong><%= error_message %></strong>
      </p>
      <p>
        <%= content_for :error_details %>
      </p>
    <% else %>
      <%= error_message %>
    <% end %>
  </div>

  <span class="close-handler" role="button" tabindex="0" aria-label="{{ ::I18n.t('js.close_popup_title') }}">
    <%= op_icon('icon-close') %>
  </span>
</div>