tested sizes, decided on adjustment.

public/css/main.css

@@ -137,8 +137,8 @@ header h1 {
     margin-bottom: 15px;
 }
 nav li {
-    font-size: 1.625em;
-    line-height: 1.15384615;
+    font-size: 1.375em;
+    line-height: 1.13636364;
     display: inline;
     padding: 0 15px;
 }