You can edit / change the code and click run button <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <style> p { border-style: solid; border-left-width: 10px; border-color: green; } </style> <script>var clicky_site_ids = clicky_site_ids || []; clicky_site_ids.push(101319977);</script><script async src="//static.getclicky.com/js"></script> <p>CSS border-left-width property example</p>