    (function () {
            const style = document.createElement('style');
            document.head.appendChild(style);
            style.sheet.insertRule(`#testDeleteRule { color: red; }`, 0);
            style.sheet.insertRule(`#testDeleteRule { color: green; }`, 1);
            style.sheet.insertRule(`#testDeleteRule { color: blue; }`, 2);
            const elm = document.getElementById('testDeleteRule');
            const sheet = style.sheet;
            sheet.deleteRule(2);
            const comput