.classroom th,
.classroom td {
  vertical-align: middle;
  text-align: center;
}

table.classroom {
   table-layout: auto;
   width: 100%;
   margin: 5px 0px 10px;
   border-collapse: collapse;
   border-collapse: separate;
   border-spacing: 2px;

}

.classroom td {
  height: 2.5em;
  width : 19%;
  background: #f8f9fa;
}

.classroom th {
  height: 2em;
  background-color: #eef0f1;
}