.sr-only {
    /* do NOT use display: none */
    border: 0;
    clip: rect(0 0 0 0);
    height: 1px;  /* should never be 0 */
    margin: -1px;
    overflow: hidden;
    padding: 0;
    position: absolute;
    width: 1px;  /* should never be 0 */
}