.nav {
  overflow: hidden;
  width: 1050px;
  margin: 0 auto;
  padding: 0;
  display: flex;
}
.nav li {
  list-style: none;
}
.nav li a {
  display: block;
  width: 210px;
  height: 40px;
  text-align: center;
  color: #fff;
  font-size: 16px;
  line-height: 2.8;
  background: #077a27;
  text-decoration: none;
  border-right: 1px solid #eee;
  box-sizing: border-box;
}
.nav > li:hover > a {/*layer-1*/
  color: #fff;
  background: #0ca436;
}
.nav li ul {
  width: 210px;
  display: none;
  margin-left: -40px;
  position: absolute;
}
.nav > li li:hover > a {/*layer-2*/
  color: olive;
  background: #0ca436;
  color:#fff;
}
.nav li ul li a {
  border-top: 1px solid #eee;
}