.navbar-nav li:hover > ul.dropdown-menu {
  display: block;
}
.dropdown-submenu {
  position:relative;
}
.dropdown-submenu>.dropdown-menu {
  top: 0;
  left: 100%;
  margin-top:-6px;
}

/* rotate caret on hover */
.dropdown-menu > li > a:hover:after {
  text-decoration: underline;
  transform: rotate(-90deg);
}

ul.navbar-nav li:hover>a {
  /* 滑鼠移入次選單上層按鈕保持變色*/
  background: #95c232;
  color: #fff;
}