Scheduled maintenance downtime announcement (banner)

templates/base/head.tmpl

@@ -232,6 +232,18 @@
 					</div><!-- end grid -->
 				</div><!-- end container -->
 			</div><!-- end bar -->
+			<div class="ui container grid warning message">
+				<div class="content">
+					<div class="header">
+						Scheduled downtime for maintenance
+					</div>
+					<p>On <b>Monday, 24 June, 2019 at 15:00 CEST (13:00 UTC)</b> the GIN service will be unavailable until approximately<br>
+					<b>18:00 CEST (16:00 UTC)</b> on the same day.  For more information, please see the item in our <a href=https://gin.g-node.org/G-Node/Info/wiki/News#upgrades-and-downtime-)>News section</a>.</p>
+
+					<p>If this schedule severely impacts your work, please <a href=mailto:gin@g-node.org>contact us at gin@g-node.org</a>.</p>
+				</div>
+			</div>
+
 		{{end}}
 {{/*
 	</div>