#fullscreen-btn {
    -webkit-appearance: none;
    border: none;
    background: none;
    position: fixed;
    top: 0;
    right: 0;
    width: 35px;
    height: 35px;
    z-index: 9999;
    cursor: pointer;
    background-repeat: no-repeat;
    background-position: center;
    background-size: 28px;
    background-image: url('data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" width="48" height="48" viewBox="0 0 48 48"%3E%3Cpath d="M14 28h-4v10h10v-4h-6v-6zm-4-8h4v-6h6v-4H10v10zm24 14h-6v4h10V28h-4v6zm-6-24v4h6v6h4V10H28z" fill="%23fff"/%3E%3C/svg%3E');
    background-color: rgba(0, 0, 0, 0.5);
    border-bottom-left-radius: 10px;
  }
  .fullscreen #fullscreen-btn {
    background-image: url('data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" width="48" height="48" viewBox="0 0 48 48"%3E%3Cpath d="M10 32h6v6h4V28H10v4zm6-16h-6v4h10V10h-4v6zm12 22h4v-6h6v-4H28v10zm4-22v-6h-4v10h10v-4h-6z" fill="%23fff"/%3E%3C/svg%3E');
  }