index.css

/* -*- Mode: CSS -*- */
/**
 * Style sheet for index.html
 */
@import url("./normalize.css");
@import url("./link.css");

/* General rules. */

body {
    background-color: white;
    color: black;
    max-width: 900px;
    margin: 0 auto;
}

img {
    max-width: 100%;
}

/* Header rules. Put the banner image in center. */

header {
    align-items: center;
    display: flex;
    justify-content: center;
}

/* Main rules */

main {
    padding: 0em 1em;
}

main dl>dd {
    margin: 0em 0em 1em 1em;
}

/* Footer rules */

body {
    display: grid;
    grid-template-rows: auto 1fr auto;
    min-height: 100vh;
}

footer {
    border-top: 1px solid grey;
    color: black;
    font: 0.9em times, "times new roman", sans-serif;
    padding: 10px 0px;
}

footer ul,
footer ol {
    list-style-type: none;
}

footer ul {
    align-items: center;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 0;
    padding: 0;
}

#footer_copyright {
    flex: 1 auto;
}