diff --git a/examples/overlay-and-popup.html b/examples/overlay-and-popup.html
index 04521660c4..67bba0aa9b 100644
--- a/examples/overlay-and-popup.html
+++ b/examples/overlay-and-popup.html
@@ -26,44 +26,44 @@
         text-shadow: black 0.1em 0.1em 0.2em;
       }
       #popup {
-      	width: 200px;
-      	margin-left: -107px;
-      	margin-bottom: 12px;
-      	border-radius: 5px;
-      	padding: 5px;
+        width: 200px;
+        margin-left: -107px;
+        margin-bottom: 12px;
+        border-radius: 5px;
+        padding: 5px;
       }
 
 
       /* Popup CSS generated with http://cssarrowplease.com/ */
 
       .arrow_box {
-      	position: relative;
-      	background: #88b7d5;
-      	border: 2px solid #c2e1f5;
+        position: relative;
+        background: #88b7d5;
+        border: 2px solid #c2e1f5;
       }
       .arrow_box:after, .arrow_box:before {
-      	top: 100%;
-      	border: solid transparent;
-      	content: " ";
-      	height: 0;
-      	width: 0;
-      	position: absolute;
-      	pointer-events: none;
+        top: 100%;
+        border: solid transparent;
+        content: " ";
+        height: 0;
+        width: 0;
+        position: absolute;
+        pointer-events: none;
       }
 
       .arrow_box:after {
-      	border-color: rgba(136, 183, 213, 0);
-      	border-top-color: #88b7d5;
-      	border-width: 10px;
-      	left: 50%;
-      	margin-left: -10px;
+        border-color: rgba(136, 183, 213, 0);
+        border-top-color: #88b7d5;
+        border-width: 10px;
+        left: 50%;
+        margin-left: -10px;
       }
       .arrow_box:before {
-      	border-color: rgba(194, 225, 245, 0);
-      	border-top-color: #c2e1f5;
-      	border-width: 13px;
-      	left: 50%;
-      	margin-left: -13px;
+        border-color: rgba(194, 225, 245, 0);
+        border-top-color: #c2e1f5;
+        border-width: 13px;
+        left: 50%;
+        margin-left: -13px;
       }
     </style>
     <link rel="stylesheet" href="../css/ol.css" type="text/css">