:root {
    --background-darker: #CCCCCC;
    --background-lighter: #DDDDDD;
}

body {
    margin: 0;
}

header {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 50px;
    border: 2px black;
    border-bottom: solid;
    margin: 0;
    padding: 12px;
    font-size: 16pt;
    background-color: var(--background-darker);
}

header a {
    margin: 0 -1px;
    padding: 14px 24px;
    border: 2px gray;
    border-style: none solid;
    color: black;
    text-decoration: none;
}

header a:hover {
    background-color: white;
}

main {
    margin: auto;
    width: 60%;
}

@media (max-width: 960px) {
    main {
        width: 90%;
    }
}

img {
    display: block;
    width: 80%;
    margin: 0 auto;
}

code {
    background-color: var(--background-lighter);
    border-radius: 4px;
    padding: 2px;
}

footer {
    text-align: center;
    position: fixed;
    bottom: 0;
    width: 100%;
    border: 2px black;
    border-top: solid;
    background-color: var(--background-darker);
    padding: 8px 0;
    margin: 0;
}