body {
  background-color: #eee;
}

thead, tbody, tr, td, th {
  display: block;
}

tr:after {
  content: ' ';
  display: block;
  visibility: hidden;
  clear: both;
}

thead th {
  height: 30px;
}

tbody {
  overflow-y: auto;
}

tbody td, thead th {
  float: left;
}
tbody td:first-of-type, thead th:first-of-type {
  width: 100px;
}

tbody td:last-of-type, thead th:last-of-type {
  width: calc(100% - 100px);
}

div#warn {
  display: none;
  position: fixed;
  z-index: 10000;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background-color: red;
  animation: warn 0.5s linear 2s infinite alternate;
}

@keyframes warn {
  from {opacity: 0;}
  to {opacity: 1;}
}