.container {
    display: flex;
    flex-direction: column;
    align-items: center;
  }
  .row {
    display: flex;
  }
  .square {
    width: 30px;
    height: 30px;
    border: 1px solid black;
    margin: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  .center {
    background-color: lightgray;
  }
  .arrows {
    margin-top: 20px;
  }
  .arrow-up, .arrow-down, .arrow-left, .arrow-right {
    width: 0; 
    height: 0; 
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
  }
  .arrow-up {
    border-bottom: 10px solid black;
    margin-right: 5px;
  }
  .arrow-down {
    border-top: 10px solid black;
    margin-left: 5px;
  }
  .arrow-left {
    border-right: 10px solid black;
    transform: rotate(90deg);
    margin-bottom: 5px;
  }
  .arrow-right {
    border-left: 10px solid black;
    transform: rotate(90deg);
    margin-top: 5px;
  }
  .active {
    background-color: yellow; /* 或者其他你想要的高亮颜色 */
  }