JSFiddle - React, Tailwind, and code Playground

HTML

<body>Some text</body>

CSS

body {
    height:2000px;
    background-color: rgb(250, 195, 56);
}

JavaScript

var tStart = 100 // Start transition 100px from top
  , tEnd = 500   // End at 500px
  , cStart = [250, 195, 56]  // Gold
  , cEnd = [179, 217, 112]   // Lime
  , cDiff = [cEnd[0] - cStart[0], cEnd[1] - cStart[1], cEnd[1] - cStart[0]];

$(document).ready(function(){
    $(document).scroll(function() {
        var p = ($(this).scrollTop() - tStart) / (tEnd - tStart); // % of transition
        p = Math.min(1, Math.max(0, p)); // Clamp to [0, 1]
        var cBg = [Math.round(cStart[0] + cDiff[0] * p), Math.round(cStart[1] + cDiff[1] * p), Math.round(cStart[2] + cDiff[2] * p)];
        $("body").css('background-color', 'rgb(' + cBg.join(',') +')');
    });
});