jQWidgets uses a pair of CSS files - jqx.base.css and jqx.[theme name].css. The base stylesheet creates the styles related to the widget's layout like margin, padding, border-width, position. The second css file applies the widget's colors and backgrounds. The jqx.base.css should be included before the second CSS file.
Below is the list of CSS classes used by jqxSlider.<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html lang="en"><head><title>jQuery Slider Sample</title><link rel="stylesheet" href="../../jqwidgets/styles/jqx.base.css" type="text/css"/><link rel="stylesheet" href="../../jqwidgets/styles/jqx.summer.css" type="text/css"/><script type="text/javascript" src="../../scripts/jquery-1.11.1.min.js"></script><script type="text/javascript" src="../../jqwidgets/jqxcore.js"></script><script type="text/javascript" src="../../jqwidgets/jqxbuttons.js"></script><script type="text/javascript" src="../../jqwidgets/jqxslider.js"></script><script async src="https://www.googletagmanager.com/gtag/js?id=G-2FX5PV9DNT"></script><script>window.dataLayer = window.dataLayer || [];function gtag(){dataLayer.push(arguments);}gtag('js', new Date());gtag('config', 'G-2FX5PV9DNT');</script></head><body><div id='content'> <script type="text/javascript"> $(document).ready(function () { $("#jqxslider").jqxSlider({ theme: 'summer', value: 7 }); }); </script> <div id='jqxslider'></div></div></body></html>
You can see the result here: