body {
    background: url(../images/background1.jpg) center / cover;
}

summary {
    color: chocolate;
    cursor: pointer;
    text-decoration: underline;
}

summary:hover {
    text-decoration: none;
}

table {
    border-collapse: collapse;
    border: none;
    margin: 2em auto 2em 3em;
}

th,
td {
    padding: .25em;
}

th,
td:first-of-type {
    text-align: center;
}

li {
    margin-top: .5em;
    margin-bottom: .5em;
}

#introduction {
    margin-left: 3em;
}