body {
  margin: auto;
  margin-top: 5px;
  width: fit-content;
}

#game {
  display: flex;
}
#warning {
  color: red;
  font-weight: bold;
}

.board {
  background-color: #999;
  display: grid;
  grid-template-columns: auto auto auto;
  margin: 2px;
  border: black 2px solid;
}
.active {
  background-color: cyan;
}
.square {
  background-color: #555;
  margin: 2px;
  width: 1em; height: 1em;
  text-align: center;
  line-height: 1em;
  pointer-events: none;
  user-select: none;
}
.active .square:not(.captured) {
  cursor: pointer;
  pointer-events: unset;
}

.captured {
  pointer-events: none;
}
.captured.x {
  background-color: red;
}
.captured.o {
  background-color: green;
}
.captured>div {
  opacity: 0;
  
}