code: function css(key, val) {
    var style, props;
    if(!this.length) {
      return this;
    }
  
    if(key && typeof key === 'object') {
      props = key;
    }else if(key && val) {
      props = {};
      props[key] = val;
    }
  
    // get style object
    if(key === undefined) {
      style = window.getComputedStyle(this.dom[0], null);
      // TODO: convert to plain object map?
      // for the moment return CSSStyleDeclaration
      return style;
    // get single style property value
    }else if(typeof key === 'string' && !val) {
      style = window.getComputedStyle(this.dom[0], null);
      return style.getPropertyValue(key);
    }
  
    // set inline styles
    this.each(function(el) {
      el.style = el.style;
      for(var z in props) {
        el.style[z] = '' + props[z];
      }
    });
    return this;
  }
docs: Get the value of a computed style property for the first element
  in the set of matched elements or set one or more CSS properties
  for every matched element.