body{margin:0;padding:0}:root{--border_color: #000}.container{width:100vw;height:100vh;display:flex}.controls{padding:5px}.grid{width:100%;height:100%;padding:5px;box-sizing:border-box;display:flex;flex-direction:column;justify-content:center;align-items:center}.grid_row{display:flex}.grid_cell{width:20px;height:20px;border:1.2px solid var(--border_color);box-sizing:border-box}.open{background-color:#f0f8ff}.open_0{border-top:0px}.open_1{border-right:0px}.open_2{border-bottom:0px}.open_3{border-left:0px}.active{background-color:purple}