header, footer {
    position: fixed;
    right: 0;
    left: 0;
    text-align: center;
}

header {
    top: 0;
}

footer {
    bottom: 0;
}

article {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background: black;
    color: white;
    --slide-top: 0;
    --slide-left: 0;
    --slide-width: 100%;
    --slide-height: 100%;
    --slide-hue: 120;
    --duration: 0.5s;
    transition: background var(--duration);
}

section {
    display: block;
    margin: 0;
    padding: 0;
    width: var(--slide-width);
    height: var(--slide-height);

    position: fixed;
    top: var(--slide-top);
    left: var(--slide-left);

    align-content: center;
    text-align: center;
    transition: top  var(--duration), left var(--duration);
    background: hsl(var(--slide-hue) 100% 10%);
    color: hsl(var(--slide-hue) 100% 90%);
}

section[aria-current=true] {
    top: 0;
    left: 0;
}

h1 {
    font-size: 1em;
}