body {
    background-color: aquamarine;
}

main.container {
    margin: 30px auto;
    text-align: center;
    padding: 10px 20px;
    max-width: 520px;
    background: white;
}

ul#listTitle {
    padding: 0;
    font-size: large;
    font-weight: bold;
    text-align: left;
}

#mainList {
    display: flex;
    justify-content: space-between;
}

#nextTodoItem {
    font-size: small;
}