.main-menu{
width: 200px;
margin: 0;
padding: 0;
list-style: none;
}
.main-menu a{
display: block;
text-decoration: none;
padding: 10px 15px;
background: #2980b9;
color: #ffffff;
border-bottom: 2px solid #2c3e50;
}
.main-menu > li {
position: relative;
}
.main-menu .sub-menu{
position: absolute;
top: 0;
left: 180px;
z-index: 10;
width: 200px;
margin: 0;
padding: 0;
list-style: none;
}
.main-menu .opened > a{
background:#1abc9c;
}
.main-menu .opened .sub-menu a{
border-bottom: 2px solid #2ecc71;
background:#1abc9c;
}