* {
    padding: 0;
    margin: 0;
}

body {
    /*font-family: 'Times New Roman';*/
    font-family: Helvetica;
}

.wrapper {
    background: #fafafa;
    height: 70vh;
    position: relative;
}

header {
    width: 100%;
    background: #151e3d;
}

.row {
    display: flex;
    justify-content: center;
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.row-li, .col-li {
    position: relative;
    list-style: none;
    padding: 20px 50px;
    transition: 0.3s;
    box-sizing: border-box;
    display: inline-block;
}

.row-li:hover, .col-li:hover {
    background: #221199;
}

header a {
    text-decoration: none;
    color: #fff;
    display: block;
    width: 100%;
    height: 100%;
}

.col {
    position: absolute;
    display: block;
    top: 100%;
    left: 0;
    width: 100%;
    background: #000;
    transition: opacity 0.3s;
    opacity: 0;
    visibility: hidden;
}

.row-li:hover .col {
    opacity: 1;
    visibility: visible;
}

.col-li:not(:last-child) {
    border-bottom: 1px solid rgba(255,255,255,.2)
}


.wrapper .center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-family: Helvetica, sans-serif;
    user-select: none;
}

.center h1 {
    color:#151e3d;
    font-size: 48px;
    font-weight: bold;
    width: 900px;
    text-align: center;
}

.center h2 {
    color:#151e3d;
    margin-top: 10px;
    font-size: 24px;
    width: 885px;
    text-align: center;
}

.center h3 {
    color:#151e3d;
    margin-top: 10px;
    font-size: 17px;
    width: 885px;
    text-align: center;
    font-weight: lighter;
}

@media (max-width: 768px){
    header ul {
        display: block;
    }
    header ul li {
        display: block;
    }
    header ul li ul{
        width: 100%;
    }
}