Use this in the <head>
<link rel="stylesheet" href="https://undp-data.github.io/stylesheets-for-viz/style/mainStyleSheet.css">
If using as an embed script add <link rel="stylesheet" href="https://undp-data.github.io/stylesheets-for-viz/style/mainStyleSheet.css"> on the top.
To see the stylesheet in action and read the documentation visit https://icy-moss-09ab08f10.4.azurestaticapps.net/