* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    height: 100%;
    overflow: hidden;
}

body {
    font-family: Arial, sans-serif;
    display: flex;
    flex-direction: column;
}

nav {
    background-color: rgba(0, 0, 0, 0.4);
    display: flex;
    justify-content: center;
    padding: 10px 0;
    position: absolute;
    width: 100%;
    z-index: 1;
}

nav ul {
    display: flex;
}

nav li {
    list-style: none;
    margin: 0 10px;
}

nav a {
    text-decoration: none;
    color: #fff;
    font-weight: bold;
}

main {
    flex: 1;
    width: 100%;
    height: 100%;
    position: relative;
}

.potw img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: 0;
}

footer {
    background-color: rgba(0, 0, 0, 0.4);
    color: #fff;
    text-align: center;
    padding: 10px;
    font-size: 0.8em;
    position: absolute;
    bottom: 0;
    width: 100%;
    z-index: 1;
}
footer a {
    color: #fff;
    text-decoration: none;
}

footer a:hover {
    color: #ccc;
    text-decoration: underline;
}