ul.related_posts {
    display: table;
    width: 100%;
    text-align: center;
}
ul.related_posts li {
    padding: 0 97px;
    text-align: center;
    width: 25%;
    max-width: 25%;
    display: inline-block;
}
ul.related_posts {
    list-style: none;
}
.post_relation h2 {
    text-align: center;
    margin-bottom: 50px;
    font-size: 35px;
}