Elastic: Make the watermark logo gray (at least in browsers supporting background-blend-mode:luminosity)

skins/elastic/watermark.html

@@ -5,7 +5,11 @@
 <title></title>
 <style type="text/css">
 html, body { height: 100%; overflow: hidden; }
-body { background: url(images/logo.svg) center no-repeat #fff; background-size: 30%; }
+body {
+  background: url(images/logo.svg) center no-repeat #fff;
+  background-size: 30%;
+  background-blend-mode: luminosity;
+}
 body:before { content: ""; position: absolute; top: 0; bottom: 0; left: 0; right: 0; background: rgba(255, 255, 255, .85); }
 </style>
 </head>