discourse-table-builder/scss/post/table-edit-decorator.scss

.open-popup-link {
  display: inline;
  margin-inline: 0.25em;
}

.btn-edit-table {
  -webkit-user-select: none;
  -webkit-touch-callout: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

.fullscreen-table-wrapper:hover .btn-edit-table {
  opacity: 100%;
}

.mobile-view {
  .btn-edit-table {
    display: none;
  }

  .fullscreen-table-wrapper {
    position: relative;
    border: 1px solid transparent;

    &:hover {
      border: 1px solid var(--primary-low);
      table {
        opacity: 0.5;
      }
      .btn-edit-table {
        z-index: 2;
        display: block;
        position: absolute;
        top: 1rem;
        left: 1rem;
      }
    }
  }
}