body {
    background-color: black;
}

.image {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;

    /* These properties are overriden for `#image-a` and `#image-b` are animated by
   `transitionImage()` to animate opacity and smoothly wipe between images. */
    opacity: 0%;
    z-index: 0;
    transition: opacity 0s ease-in-out;
}

.image.visible {
    opacity: 100%;
    z-index: 1;
}

.text-box {
    position: fixed;
    height: fit-content;
    background-color: royalblue;
    color: white;
    font-family: sans-serif;
    border-radius: 5px;
    border-width: 2px;
    border-style: solid;
    border-color: white;
}

.text-box h1 {
    font-style: italic;
    font-family: monospace;
    margin: 10px;
}

.text-box p {
    margin: 5px;
}

.text-box a {
    color: inherit;
    font-weight: bold;
    text-decoration: none;
}

.text-box nav a {
    font-weight: initial;
    font-style: italic;
}

a:hover {
    text-decoration: underline;
    font-style: italic;
}

.text-box hr {
    margin: 7px;
    border-color: inherit;
}

#message {
    width: fit-content;
    z-index: 2;
    opacity: 0%;
    transition: opacity 1s ease-in;
}

#message.visible {
    opacity: 100%;
    transition: opacity 0.1s ease-out;
}

#help {
    width: 20em;
    z-index: 3;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}