教师端1期需求ui优化

src/views/course/CourseManage.vue

@@ -87,7 +87,7 @@
             </el-col>
 
             <el-col :span="6">
-              <div class="grid-content bg-purple resetDatePicker">
+              <div :class="['grid-content', 'bg-purple', 'resetDatePicker', !studyDateTime||studyDateTime.length==0?'noSplitDatePicker':'']">
                 <el-date-picker value-format="yyyy-MM-dd" v-model="studyDateTime" type="daterange" align="right"
                   unlink-panels range-separator="至" start-placeholder="学习时长" :picker-options="pickerOptions">
                 </el-date-picker>
@@ -1048,13 +1048,14 @@ export default {
 
 <style lang="scss">
 #courseManage {
-  .resetDatePicker {
+  .noSplitDatePicker {
     /* 隐藏范围选择器的分隔符和占位符 */
     .el-range-separator,
     .el-range__close-icon {
       display: none !important;
     }
-
+  }
+  .resetDatePicker {
     .el-date-editor {
       width: 250px;
     }