styles.css

body {
    margin: 0;
    font-family: 'Nanum Gothic', sans-serif;
}

.logo {
    width: 100px;
    margin-top: -40px;
}

.nav {
    display: flex;
    justify-content: center;
    padding: 20px 0;
}

ul {
    display: flex;
}

li {
    list-style-type: none;
    padding: 20px;
}

.row {
    display: flex;
}

.container {
    width: 20%;
    position: relative;
    padding: 2px;
    transition: transform 500ms;
    display: block;
}

.container img {
    width: 100%;
    opacity: 1;
    height: auto;
    display: block;
}

.row .container:focus,
.row .container:hover {
    transform: scale(1.5);
    z-index: 1;
}

.middle {
    transition: .5s ease;
    opacity: 0;
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    left: 50%;
    width: 50%;
    height: 50%;
    text-align: center;
}

.container:hover .middle {
    opacity: 1;
}

.text {
    color: white;
    font-size: 16px;
    padding: 16px 32px;
}

.footer {
    display: flex;
    justify-content: center;
    position: fixed;
    bottom: 0;
    padding: 30px 0;
    width: 100%;
}

a {
    text-decoration: none;
    color: black;
}

@media only screen and (max-width: 1500px) {
    .text {
        font-size: 10px;
        padding: 32px 16px;
    }
}

@media only screen and (max-width: 800px) {
    .extra-item {
        display: none;
    }

    .container {
        width: 100%;
    }

    .row .container:focus,
    .row .container:hover {
        transform: none;
        z-index: 1;
    }

    .footer {
        position: relative;
    }
}