code: function isBoldBroken(document) {
    var body = document.getElementsByTagName('body')[0];
    var terminal = document.createElement('div');
    terminal.className = 'terminal';
    var line = document.createElement('div');
    var el = document.createElement('span');
    el.innerHTML = 'hello world';
    line.appendChild(el);
    terminal.appendChild(line);
    body.appendChild(terminal);
    var w1 = el.scrollWidth;
    el.style.fontWeight = 'bold';
    var w2 = el.scrollWidth;
    body.removeChild(terminal);
    return w1 !== w2;
  }
docs: if bold is broken, we can't use it in the terminal.