ul {
  /* 取消ul預設的內縮及樣式 */
  margin: 0;
  padding: 0;
  list-style: none;
}

ul.drop-down-menu {
  border: #ccc 1px solid;
  display: inline-block;
  font-family: 'Open Sans', Arial, sans-serif;
  font-size: 13px;
}

ul.drop-down-menu li {
  position: relative;
  white-space: nowrap;
  border-right: #ccc 1px solid;
}

ul.drop-down-menu>li:last-child {
  border-right: none;
}

ul.drop-down-menu>li {
  float: left;
  /* 只有第一層是靠左對齊*/
}

ul.drop-down-menu a {
  background-color: #9BBB59;
  color: #fff;
  display: block;
  padding: 0 30px;
  text-decoration: none;
  line-height: 40px;
  font-weight: bold;
  font-size: 16px;
  font-family: "微軟正黑體";
}

ul.drop-down-menu a:hover {
  /* 滑鼠滑入按鈕變色*/
  background-color: #339933;
  color: #fff;
}

ul.drop-down-menu li:hover>a {
  /* 滑鼠移入次選單上層按鈕保持變色*/
  background-color: #339933;
  color: #fff;
}

ul.drop-down-menu ul {
  border: #ccc 1px solid;
  position: absolute;
  z-index: 99;
  left: -1px;
  top: 100%;
  min-width: 180px;
}

ul.drop-down-menu ul li {
  border-bottom: #ccc 1px solid;
}

ul.drop-down-menu ul li:last-child {
  border-bottom: none;
}

ul.drop-down-menu ul ul {
  /*第三層以後的選單出現位置與第二層不同*/
  z-index: 999;
  top: 10px;
  left: 90%;
}

ul.drop-down-menu ul {
  /*隱藏次選單*/
  display: none;
}

ul.drop-down-menu li:hover>ul {
  /* 滑鼠滑入展開次選單*/
  display: block;
}