Посоветуйте оптимизацию 28/28

Курсы §13. Мастерская: создаём меню
1

html,
body {
margin: 0;
padding: 0;
}

body {
width: 380px;
min-height: 280px;
padding: 10px;
font-family: “Arial”, sans-serif;
font-size: 14px;
line-height: 1.4;
background: #ecf0f1;
}
.main-menu {
padding: 0;
margin: 0;
width: 200px;
background: #2980b9;
text-decoration: none;

}
.main-menu >li {
position: relative;
padding: 10px 15px;
border-bottom: 2px solid #2c3e50;
}
.main-menu a {
display: block;
color: #ffffff;
text-decoration: none;
}
.main-menu .sub-menu {
list-style: none;
position: absolute;
top: 0;
left: 140px;
z-index: 10;
}
.main-menu .sub-menu a{
padding: 10px 15px;
background: #1abc9c;
border-bottom: 2px solid #2ecc71;
padding-right: 60px;

}

.main-menu .opened {
background: #1abc9c;
}

2

Лови

ul {
width:200px;
background-color:#2980b9;
list-style:none;
margin:0;
padding:0;
}

a {
display:block;
color:white;
padding:10px 15px;
border-bottom:2px solid #2c3e50;
text-decoration:none;
}

.opened {
position:relative;
}

.sub-menu {
position:absolute;
left:180px;
top:0px;
}

.opened a {
background-color:#1abc9c;
border-bottom:2px solid #2ecc71;
}

.opened>a {
border-bottom:2px solid #2c3e50;
}