I'm reading the bootstrap doc and I read this ... Bootstrap v4.3 ships with the option to enable responsive font sizes, allowing the text to scale more naturally across device and viewport sizes.RFS can be enabled by changing the $enable-responsive-font-sizes Sass variable to true.
My question is, how can I enable this feature with CDN Bootstrap
https://getbootstrap.com/docs/4.3/content/typography/#responsive-font-sizes
If you need to use CDN you can add the following.
<link href="https://cdn.jsdelivr.net/gh/coliff/bootstrap-rfs/bootstrap-rfs.css" rel="stylesheet">