If you are running dashboards internally/at a customer where you control the browser running the Kibana, you can also use browser injected css. In firefox you can use the userContent.css (http://kb.mozillazine.org/index.php?title=UserChrome.css&printable=yes) or install a plugin in chrome like stylus or similar (https://chrome.google.com/webstore/detail/stylus/clngdbkpkpeebahjckkjfobafhncgmne?hl=en)