28/28 100%


#1
ul {
  margin: 0;
  padding: 0;
  list-style: none;
  width: 200px;
  background: #2980b9;
}


.main-menu .open {
  position: relative;
  background: #1abc9c;
}
.main-menu a {
  display: block;
  padding: 10px 15px;
  border-bottom: 2px solid #2c3e50;  
  color: white;
  text-decoration:none;
}

.main-menu .sub-menu {
  position: absolute;
  left: 180px;
  top: 0;
  background: #1abc9c;
  z-index: 10;
}

.main-menu .sub-menu a {border-color: #2ecc71;}