JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Hi!  Test!</h1> 
<h2>Light Example!</h2>

CSS

H1 {          
    font-weight: 800; 
}

JavaScript

$('H1').animate({'font-weight': 100 }, 
      { 
          duration: 10000,
          step: function(now, opts){ 
              opts.now = Math.round(now/100)*100; 
              //$("body").append(opts.now+"<br>");
          } ,
          complete: function() { $('H1').append('  Done!'); }
      }
      );