.section-404help ul {
    margin: 0 auto;
    display: inline-block;
}
.section-404help li {
    margin: 0 auto;
    float: left;
}
.section-404help li a {
    padding: 17px 21px;
    margin: 0 8px;
}

@media (max-width: 767px) {
    .section-404help ul {
        margin: 0 auto;
        display: block;
    }
    .section-404help li {
        float: none;
        margin-bottom: 16px;
    }
    .section-404help li a {
        margin: 0;
        width: 100%;
        max-width: 400px;
    }
}