.error404 .text-block {
    text-align: center;
}

body.error404 form .gsc-search-button-v2,
body.error404 form .gsc-search-button-v2:hover,
body.error404 form .gsc-search-button-v2:focus {
    border-color: #9b0000;
    background-color: #c5050c;
    background-image: none;
    filter: none;
}

body.error404 .sidebar-layout-main-content {
    float: none;
    margin: 0 auto;
}