#back-to-top {
    background: rgba(0,0,0,.5);
    border-radius: 5px;
    display: none;
    position: fixed;
    right: 2rem;
    bottom: 3rem;
    height: 36px;
    text-align: center;
    width: 36px;
}  
.page-header h1, .categories-list h1 {
    font-size: 2rem;
    font-weight: 600;
}