.nav {
    overflow: hidden;
    width 750px;
    margin: 0 auto;
    padding: 0;
    display: flex;
}
.nav li {
    list-style: none;
    z-index: var(--menu-z-index);
}
.nav li a {
    display: block;
    width: 150px;
    height: 40px;
    text-align: center;
    color: #fff;
    font-size: 14px;
    line-height: 2.8;
    background: #9fb7d4;
    text-decoration: none;
    border-right: 1px solid #eee;
    box-sizing: border-box;
    z-index: var(--menu-z-index);
}

.nav > li:hover > a {/*layer-1*/
  color: orange;
  background: #afc6e2;
}

.nav > li.disabled > a {/*layer-1*/
  color: white;
  background: white;
}

.nav li ul {
  width: 150px;
  display: none;
/*  margin-left: -40px;*/
  position: absolute;
    z-index: var(--menu-z-index);

  hight: 30px;
}

.nav > li li:hover > a {/*layer-2*/
  color: olive;
  background: #afc6e2;

}
.nav li ul li a {
  border-top: 1px solid #eee;
    z-index: var(--menu-z-index);

}