JSFiddle - React, Tailwind, and code Playground

HTML

Height of Body is: <span id="height"></span>.
Height of Viewport is: <span id="viewportheight"></span>

<div style="height: 500px; background-color: red; width: 100px;"></div>

CSS

html, body {
    min-height: 100%;
}
body {
    background-color: lightblue;
}

JavaScript

$(function() {
    $(window).resize(function() {
        $('#height').text($('body').height());
        $('#viewportheight').text($(window).height());
    });
    
    $('#height').text($('body').height());
    $('#viewportheight').text($(window).height());
});