.main-nav {
    position: relative ;
    
    width: 600px;
    height: 150px;
}

    .main-nav li {
        list-style: none;
        position: absolute;
        width: 200px;
        height: 200px;
        background: #000;
        transform: rotate(45deg);
        transition: 0.5s;
        margin: -100px;
        overflow: hidden;
        opacity: 1;
    }

        .main-nav li:hover {
            opacity: 1;
        }

        .main-nav li.item1 {
            top: 0;
            left: -25%;
        }

        .main-nav li.item2 {
            bottom: 0;
            left: 0%;
        }

        .main-nav li.item3 {
            top: 0;
            left: 25%;
        }

        .main-nav li.item4 {
            bottom: 0;
            left: 50%;
        }

        .main-nav li.item5 {
            top: 0;
            left: 75%;
        }

        .main-nav li.item6 {
            bottom: 0;
            left: 100%;
        }

        .main-nav li.item7 {
            top: 0;
            left: 125%;
        }

        .main-nav li .bg {
            width: 100%;
            height: 100%;
            transform: scale(1.1);
        }

        .main-nav li.item1 .bg {
            background: url(../images/photosection/1.png);
            background-size: cover;
            background-position: center;
        }

        .main-nav li.item2 .bg {
            background: url(../images/photosection/2.png);
            background-size: cover;
            background-position: center;
        }

        .main-nav li.item3 .bg {
            background: url(../images/photosection/3.png);
            background-size: cover;
            background-position: center;
        }

        .main-nav li.item4 .bg {
            background: url(../images/photosection/4.png);
            background-size: cover;
            background-position: center;
        }

        .main-nav li.item5 .bg {
            background: url(../images/photosection/5.png);
            background-size: cover;
            background-position: center;
        }

        .main-nav li.item6 .bg {
            background: url(../images/photosection/6.png);
            background-size: cover;
            background-position: center;
        }

        .main-nav li.item7 .bg {
            background: url(../images/photosection/7.png);
            background-size: cover;
            background-position: center;
        }