Basic css to create a responsive table.

table-responsive.css

table.table-a11y {
  display: block;
}

table.table-a11y thead, 
table.table-a11y tbody, 
table.table-a11y tfoot {
  display: block;
}

table.table-a11y tr {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  width: 100%;
}

@media (min-width: 1024px) {
  table.table-a11y tr {
    flex-direction: row;
  }
}