gristlabs_grist-core/app/client/widgets/FieldBuilder.css

.transform_editor {
  width: 90%;
  margin: 5px auto;
  border: 1px solid #DDDDDD;
}

.transform_menu {
  padding: 5px 0;
  margin: 5px;
  border-top: 1px solid rgba(200, 200, 200, .3);
  border-bottom: 1px solid rgba(200, 200, 200, .3);
}

.fieldbuilder_settings {
  background-color: var(--grist-theme-right-panel-field-settings-bg, #e8e8e8);
  margin: 1rem -1px -4px -1px;
  padding-bottom: 1px;
}

.fieldbuilder_settings_header {
  height: 2rem;
  margin-top: 0px;
  margin-bottom: 0px;
}

.fieldbuilder_settings_button {
  display: inline-block;
  float: right;
  padding: 0 1rem;
  border-radius: 5px;
  background-color: var(--grist-theme-right-panel-field-settings-button-bg, lightgrey);
}