index.scss

.Window_Tetris {
  .game-root {
    height: 500px;
    margin: 0 auto;
    outline: 3px solid #061006;
    width: 250px;
  }

  .game-root > div::before {
    background-color: #63796c;
    border: 3px solid #758c7a;
    bottom: 3px;
    content: ' ';
    left: 3px;
    position: absolute;
    right: 3px;
    top: 3px;
  }

  .game-root > div.filled::before {
    background-color: #061006;
    border-color: #758c7a;
  }

  .game-root > div.filled {
    background-color: #061006;
  }

  .game-root > div {
    background-color: #63796c;
    border: 1px solid #758c7a;
    box-sizing: border-box;
    float: left;
    height: 25px;
    position: relative;
    width: 25px;
  }
}