*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
.main-nav{
    margin-top: 10px;
    list-style: none;
    padding-left: 0;
    background-color: #159c9c;
}
.main-nav-item{
    display: inline-block;
    border-right: 3px solid #ffffff;
}
.main-nav-item a{
    color: white;
    padding: 2px 8px;
    text-decoration: none;
    border-radius: 2px;
    /*background-color: red;*/
}
/*pseudo clases*/
.main-nav-item a:hover{
    color: blue;
}
.main-nav-item a:active{
    color: chocolate;
}
/*
.main-nav-item a::after{
    content: " | ";
}*/

main{
    width: 100%;
    height: 500px;
    border: 10px solid gray;
    padding: 20px 35px;
}