var doc = document;
var head = doc.getElementsByTagName("head").item(0);

exports.addStyles = function (css) {
  var style = doc.createElement("style");

  style.setAttribute("type", "text/css");

  // https://msdn.microsoft.com/en-us/library/ms535871(v=vs.85).aspx
  var internetExplorerSheetObject =
    style.sheet || // Edge/IE11.
    style.styleSheet; // Older IEs.

  if (internetExplorerSheetObject) {
    internetExplorerSheetObject.cssText = css;
  } else {
    style.appendChild(doc.createTextNode(css));
  }

  return head.appendChild(style);
};