Use style from ui.css.

guacamole/src/main/webapp/client.xhtml

@@ -23,6 +23,7 @@
 
     <head>
         <link rel="icon" type="image/png" href="images/guacamole-logo-64.png"/>
+        <link rel="stylesheet" type="text/css" href="styles/ui.css"/>
         <link rel="stylesheet" type="text/css" href="styles/client.css"/>
         <link rel="stylesheet" type="text/css" href="styles/keyboard.css"/>
         <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no, target-densitydpi=device-dpi"/>