html,body{
  overflow:hidden;
}
*{
  box-sizing:border-box;
}

table{
  width:100%;
  height:100%;
  min-height:calc(100vh - 40px);
}
td{
  cursor:pointer;
}
i{
  display:block;
  width:100%;
  height:100%;
}
td.select i{
  border:4px solid #00ff00;
}
td:hover i{
  border:4px solid #fff;
}
td.open{
  background-color:#000;
  cursor:crosshair;
}
td.open i{
  border:4px solid #000;
  background-color:#000;
}