body {
  text-align: center;
  margin: 0;
}

.tic-tac-toe {
  height: 450px;  
  width: 450px;  
  margin: 50px auto 30px auto;
  position: relative;
  background-color: #E6E6FA;
}

.tic-tac-toe input[type="radio"] {
  display: none;
}

.tic-tac-toe input[type="radio"].turn-1 + label {
  z-index: 1;
  display: block;
}

.tic-tac-toe input[type="radio"].turn-1:checked + label {
  cursor: default;
  background-color: red;
  z-index: 10 !important;
}

.tic-tac-toe input[type="radio"].turn-1.field-9:checked ~ .turn-2.field-3 + label {
  display: block;
  cursor: default;
  background-color: green;
  z-index: 2;
}

.tic-tac-toe label {
  background-color: #78bec5;
  height: 140px;
  width: 140px; 
  display: none;
  margin: 5px;
  position: absolute;
  cursor: pointer;
  color: #fff;
  -moz-transition: background-color 0.3s;
  -o-transition: background-color 0.3s;
  -webkit-transition: background-color 0.3s;
  transition: background-color 0.3s;
}

.tic-tac-toe input[type="radio"].left + label {
  left: 0px;
  right: 300px;
}

.tic-tac-toe input[type="radio"].middle + label {
  left: 150px;
  right: 150px;
}

.tic-tac-toe input[type="radio"].right + label {
  left: 300px;
  right: 0px;
}


.tic-tac-toe input[type="radio"].top + label {
  top: 0px;
  bottom: 300px;
}

.tic-tac-toe input[type="radio"].center + label {
  top: 150px;
  bottom: 150px;
}

.tic-tac-toe input[type="radio"].bottom + label {
  top: 300px;
  bottom: 0px;
}