.menu-content {
    margin: 0 auto;
    padding: 1cm 0;
    text-align: left;
    font: 30px;
    background: black;
}

.menu-content a {
    color: #FFF;
    text-decoration: none;
    margin: 0px 15px;
    padding: 10px 15px;
    position: relative;
    cursor: pointer;
}

.pull-right a:before {
    position: absolute;
    width: 3px;
    height: 100%;
    left: 0;
    top: 0;
    content: '';
    background: white;
    opacity: 0.5;
    transition: all 0.5s;
}

.pull-right-current a:before {
    background: blue;
}

.pull-right a:hover:before {
    width: 200px;
}