.content-center {
    min-height: calc(100vh - 100px);
    display: grid;
    place-items: center;
    padding: 20px 0;
}

.auth-card {
    width: min(100%, 430px);
}

@media (max-width: 600px) {
    .content-center {
        min-height: auto;
        place-items: start stretch;
        padding: 42px 0 24px;
    }

    .auth-card {
        width: 100%;
        border: 0;
        padding: 0;
        background: transparent;
    }

    .auth-card h1 {
        font-size: 34px;
        line-height: 1.08;
    }

    .auth-card .muted { margin-bottom: 28px; }
    .auth-card .btn { width: 100%; margin-top: 4px; }

    .helper-text {
        margin-top: 18px;
        font-size: 15px;
    }
}