styles.css

:root {
    --table-header-text-color: #fff;
    --table-header-color: #04AA6D;
    --row-selection-color: #bbb;
    --row-hover-color: #ddd;
    --row-odd-color: #fffff;
    --row-even-color: #f2f2f2;
    --table-border-color: #bbb;
}

main {
    display: grid;
    grid-template-columns: 1fr;
    place-content: center;
    place-items: center;
    gap: 1rem;
    padding: 1em;
}

main>article {
    align-self: start;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    padding: 0.5em;
    gap: 1em;
}

main>article section {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    flex-wrap: wrap;
    margin: 0.5em;
}

main table {
    font-family: Arial, Helvetica, sans-serif;
    border-collapse: collapse;
    text-align: center;
    max-width: 500px;
}

main table th,
main table td {
    border: 1px solid var(--table-border-color);
    padding: 8px;
}

main table td {
    width: 20px;
}

main table tr:nth-child(even) {
    background-color: var(--row-even-color);
}

main table tr[data-selected="true"] {
    background-color: var(--row-selection-color);
}

main table tbody[data-selected-only="true"]>tr:not([data-selected="true"]) {
    display: none;
}

main table tbody[data-selected-only="true"]>tr[data-selected="true"]:not([hidden]):nth-child(odd) {
    background-color: var(--row-odd-color);
}

main table tbody[data-selected-only="true"]>tr[data-selected="true"]:not([hidden]):nth-child(even) {
    background-color: var(--row-even-color);
}

main table>tbody>tr:hover {
    background-color: var(--row-hover-color);
}

main table td:nth-child(2),
main table td:nth-child(5),
main table td:nth-child(9) {
    border-right-width: 4px;
}

main table th {
    padding-top: 12px;
    padding-bottom: 12px;
    background-color: var(--table-header-color);
    color: var(--table-header-text-color);
}

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

@media screen and (min-width: 790px) {
    main {
        grid-template-columns: 1fr 1fr;
    }

    main article:nth-child(odd) {
        justify-self: end;
    }

    main article:nth-child(even) {
        justify-self: start;
    }

    main table td {
        width: 24px
    }
}