html,
body {
    height: 100%;
}

body {
    display: flex;
    align-items: center;
    padding-top: 40px;
    padding-bottom: 40px;
    background-color: #f5f5f5;
}

.bd-placeholder-img {
    font-size: 1.125rem;
    text-anchor: middle;
    -webkit-user-select: none;
    -moz-user-select: none;
    user-select: none;
}

@media (min-width: 768px) {
    .bd-placeholder-img-lg {
        font-size: 3.5rem;
    }
}

.main-container {
    width: 100%;
    max-width: 450px;
    padding: 15px;
    margin: auto;
    text-align: center;
}