JSFiddle - React, Tailwind, and code Playground

CSS

.alert {
    padding: 1em;
    background: yellow;
}

JavaScript

(function () {
    var trident = {
      string: navigator.userAgent.match(/Trident\/(\d+)/)
    };

    trident.version = trident.string ? parseInt(trident.string[1], 10) : null;

    if (!trident.string || trident.version < 6) {
      document.body.innerHTML = '<div class="alert">Not supported.</div>' + document.body.innerHTML;
    }
})();