ONOS-2060: Add strong discouragement message if trying to deactivate or uninstall drivers.

Change-Id: I94b168738f3dbf5d692165cadf954ba9fffc5ae6
diff --git a/web/gui/src/main/webapp/app/view/app/app.css b/web/gui/src/main/webapp/app/view/app/app.css
index ec4972a..c015459 100644
--- a/web/gui/src/main/webapp/app/view/app/app.css
+++ b/web/gui/src/main/webapp/app/view/app/app.css
@@ -41,6 +41,18 @@
     color: #c55;
 }
 
+#app-dialog p.strong {
+    font-weight: bold;
+}
+.light #app-dialog p.strong {
+    color: red;
+    background-color: #ff0;
+}
+.dark #app-dialog p.strong {
+    color: #c55;
+    background-color: #dd4;
+}
+
 
 .light #app-dialog.floatpanel.dialog {
     background-color: #fff;