src/dnd-service.js
function injectStyles() {
  if (_stylesInjected) return;
  _stylesInjected = true;

  let node = doc.createElement('style');
  node.innerHTML = css;
  node.type = 'text/css';

  if (doc.head.childNodes.length > 0) {
    doc.head.insertBefore(node, doc.head.childNodes[0]);
  } else {
    doc.head.appendChild(node);
  }
}
function injectStyles() {
  if (_stylesInjected) return;
  _stylesInjected = true;

  let node = doc.createElement('style');
  node.innerHTML = css;
  node.type = 'text/css';

  if (doc.head.childNodes.length > 0) {
    doc.head.insertBefore(node, doc.head.childNodes[0]);
  } else {
    doc.head.appendChild(node);
  }
}
function injectStyles ( ) { if ( _stylesInjected ) return ; _stylesInjected = true ; let node = doc . createElement ( 'style' ) ; node . innerHTML = css ; node . type = 'text/css' ; if ( doc . head . childNodes . length > 0 ) { doc . head . insertBefore ( node , doc . head . childNodes [ 0 ] ) ; } else { doc . head . appendChild ( node ) ; } }
copied from aurelia-pal-browser
copied from aurelia - pal - browser