body.single-post article.post,
body.single-post .site-main > article,
body.single-post main > article {
    max-width: 900px !important;
    width: 100% !important;
    margin-left: auto !important;
    margin-right: auto !important;
    background-color: #ffffff !important;
    padding: 2rem;
    box-sizing: border-box;
}