Horizontally distribute all items

justify-to-center.css

/* JUSTIFY TO CENTER */
#subMenu ul{
  vertical-align: middle; /*Or anything else*/
  width: 100%;
  max-width: 960px; /*Allow items to be distributed only in this maximum space, remove if you need all 100% */
  margin: 0 auto; /*Center*/
  text-align: justify;
}

#subMenu ul:after{
  content: "";
  padding-right: 100%;
  display: inline-block;
  vertical-align: top;
}

#subMenu ul li{
  display: inline-block;
}