```css
nav {
    position: sticky;
    top: 0;
    background: black;
    padding: 15px;
}

nav {
    position: sticky;
    top: 0;
    background: black;
    padding: 15px;
}

section {
    position: relative;
}

img {
    position: static;
    width: 100%;
    height: 1000px;
}

h1 {
    position: absolute;
    top: 50%;
    left: 45%;
    color: white;
}

footer {
    position: relative;
    left: 0;
    padding: 20px;
}

.top {
    position: fixed;
    right: 10px;
    bottom: 10px;
}
```