main {
    background-color: #ddd;
}
.dark main {
    background-color: #2b2b31;
}

.card {
    margin: auto;
    width: 100%;
    max-width: 540px;
}

.card-logo {
    width: 100%;
    margin-left: 10px;
    margin-right: 10px;
    max-width: 300px;
}