body {
  -webkit-touch-callout: none;
  /* iOS Safari */
  -webkit-user-select: none;
  /* Safari */
  -khtml-user-select: none;
  /* Konqueror HTML */
  -moz-user-select: none;
  /* Firefox */
  -ms-user-select: none;
  /* Internet Explorer/Edge */
  user-select: none;
  /* Non-prefixed version, currently
     supported by Chrome and Opera */
}

html, body {
  height: 100%;
}

body {
  background-color: #444;
  color: #fff;
  overflow: hidden;
}

.container, .container .game-area .cell {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 100%;
}
.container .game-area, .container .game-area .cell .game-area {
  width: 304px;
  height: 304px;
  display: flex;
  flex-wrap: wrap;
  cursor: default;
}
.container .game-area .message {
  width: 100%;
  font-size: 150%;
  text-align: center;
}
.container .game-area .message .choice {
  font-size: 200%;
  color: #aaa;
}
.container .game-area .message .choice:hover, .container .game-area .message .choice:active {
  color: #fff;
  cursor: pointer;
}
.container .game-area .cell {
  width: 100px;
  height: 100px;
  font-size: 500%;
}