table {overflow: hidden;}
td, th, tr {position: relative; outline: 0;}
body:not(.nohover) tbody tr:hover {background-color: #ffa;}
td:hover::after,thead th:not(:empty):hover::after,td:focus::after,
thead th:not(:empty):focus::after {content: '';height: 10000px;left: 0;position: absolute; top: -5000px;width: 100%;z-index: -1;}
td:hover::after,th:hover::after {background-color: #ffa;}
td:focus::after,th:focus::after {background-color: lightblue;}
td:focus::before,tbody th:focus::before {content: '';height: 100%;top: 0;left: -5000px;position: absolute;width: 10000px;z-index: -1;}