去掉拼音组件预览背景色

src/views/book/courseware/preview/components/pinyin_base/PinyinBasePreview.vue

@@ -806,7 +806,8 @@ export default {
   .option-content {
     padding: 5px 15px;
     color: #706f78;
-    background-color: $content-color;
+
+    // background-color: $content-color;
     border: 1px solid $content-color;
     border-radius: 4px;