主题色容错处理

src/views/book/courseware/preview/components/fill/FillPreview.vue

@@ -6,7 +6,7 @@
     <div class="main" :style="getMainStyle()">
       <AudioFill
         v-if="data.audio_file_id.length > 0"
-        :color="data.unified_attrib.topic_color"
+        :color="data.unified_attrib?.topic_color"
         :file-id="data.audio_file_id"
       />
       <div class="fill-wrapper">