diff --git a/lib/report/common/defaults.js b/lib/report/common/defaults.js
index 9c7d7881..fae736fe 100644
--- a/lib/report/common/defaults.js
+++ b/lib/report/common/defaults.js
@@ -25,11 +25,12 @@ module.exports = {
     colorize: function (str, clazz) {
         /* istanbul ignore if: untestable in batch mode */
         if (supportsColor) {
-            switch (clazz) {
-                case 'low' : str = '\x1B[91m' + str + '\x1B[0m'; break;
-                case 'medium': str = '\x1B[93m' + str + '\x1B[0m'; break;
-                case 'high': str = '\x1B[92m' + str + '\x1B[0m'; break;
-            }
+            var colors = {
+                low: '31;1',
+                medium: '33;1',
+                high: '32;1'
+            };
+            return '\u001b[' + colors[clazz] + 'm' + str + '\u001b[0m';
         }
         return str;
     },