my-website/static/css/general.css

html {
    font-family: monospace;
}

header, footer {
    text-align: center;
    margin: 0;
    border: 0;
}

.globalnav{
    display: flex;
    flex-direction: row;
    border: none;
}

.globalnav-element {
    display: inline-block;
    flex-grow: 1;
    padding: 0.5em 0;
    margin: 0 1px;
}

code {
    display: inline-block;
    background-color: lightgray;
    color: green;
}

@media (prefers-color-scheme: dark) {
    html {
        background-color: black;
        color: white;
    }

    .globalnav-element {
        background-color: #222;
    }

    code {
        background-color: #444;
        color: lawngreen;
    }

    a {
        color: lightskyblue;
    }
}

@media (prefers-color-scheme: light) {
    html {
        background-color: white;
        color: black;
    }

    .globalnav-element {
        background-color: #ddd;
    }

    code {
        color: green;
    }
}