bundle.css

* {
  box-sizing: border-box;   
  -moz-box-sizing: border-box;
}

html, body { 
  margin: 0; 
  padding: 0; 
  overflow: hidden; 
}

.board {
  outline: none;
}

.board-row {
  height: 40px;
}

.square {
  height: 40px;
  width: 40px;
  display: inline-block;
}

.square.active {
  border-color: black;
  border-width: 1px;
  border-style: solid;
}

.square.black {
  background-color: black;
}

.square.red {
  background-color: red;
}

.square.green {
  background-color: green;
}

.square.blue {
  background-color: blue;
}

.square.purple {
  background-color: purple;
}

.square.yellow {
  background-color: yellow;
}