style(统计业务): 统一统计页面样式和布局

- 引入公共样式文件，简化各统计页面的样式管理
- 优化统计页面的容器布局，采用flex布局以提升响应式表现
- 统一表单项的样式，确保一致性和可读性
- 移除冗余的样式定义，提升代码整洁度

src/views/modules/statisticsBusiness/courseStatistics/courseStatistics.vue

@@ -414,15 +414,10 @@ export default {
 </script>
 
 <style scoped lang="less">
-.course-statistics-container {
-  display: flex;
-  flex-direction: column;
-  height: calc(100vh - 220px);
+@import '../styles/statistics-common.less';
 
-  .table-container {
-    flex: 1;
-    overflow: hidden;
-  }
+.course-statistics-container {
+  .sb-page-height-with-table();
 }
 
 .dialog-header {
@@ -438,11 +433,7 @@ export default {
   color: #303133;
 }
 
-.el-form .el-form-item {
-  margin-bottom: 10px !important;
-}
+.sb-form-item-ten();
 
-/deep/ .el-dialog__wrapper .el-dialog__body {
-  padding-top: 0 !important;
-}
+.sb-dialog-body-no-top-padding();
 </style>