h1 {
    text-align: center;
}

.light_container {
    color: black;
    background-color: white;
    text-align: center;
    padding: 10px;
}

.dark_container {
    color: white;
    background-color: #1d1d1d;
    padding: 10px;
}

table,
th,
td {
    border: 1px solid gray;
    text-align: center;
    border-collapse: collapse;
}

table {
    margin-left: auto;
    margin-right: auto;
}

.back {
    text-align: center;
    margin: 20px 10px;
}

footer {
    text-align: center;
}