.side_nav {
    color: gray;
    text-decoration: none;
}

.side_nav.active, .side_nav:focus, .side_nav:hover {
    color: white;
    font-weight: bolder;
    background-color: #00bb31;
}

.article_card:focus, .article_card:hover {
    border-style: solid;
    border-color: #00bb31;
}

.card_title {
    color: black;
    text-decoration: none;
}

.card_title.active, .card_title:focus, .card_title:hover {
    color: #00bb31;
}

.article_cover {
    height: 200px;
}