Improve design of maintenance messages

Change-Id: Icc1ab812aab065e29a7f61a936b4275d3d7cca72
diff --git a/dev/scss/base/icons.scss b/dev/scss/base/icons.scss
index 64b9a60..749715c 100644
--- a/dev/scss/base/icons.scss
+++ b/dev/scss/base/icons.scss
@@ -33,3 +33,4 @@
 $fa-plugin:       "\f1e6";
 $fa-referto:      "\f0c5";
 $fa-redo:         "\f01e";
+$fa-warn:         "\f071";