tmagic-editor/packages/editor/src/theme/props-panel.scss

.m-editor-props-panel {
  padding: 0 10px;

  .el-form-item__label {
    font-size: 12px;
  }

  .m-fieldset {
    legend {
      font-size: 12px;
    }
  }

  .el-tabs__item {
    font-size: 12px;
  }

  span,
  a,
  p {
    font-size: 12px;
  }
}

.m-editor-props-panel-popper {
  span,
  a,
  p {
    font-size: 12px;
  }
}