.resizer {
  width: 10px;
  background-color: #3e3e42;
  cursor: col-resize;
  box-shadow: 0 0 3px white;
}

@media (max-width: 768px) {
  .container {
    flex-direction: column;
  }

  .left-panel, .right-panel {
    width: 100%;
    height: 50vh;
  }

  .resizer {
    width: 100%;
    height: 10px;
    cursor: row-resize;
  }
}