fix: 修复问卷预览弹窗样式选择器组断裂导致的构建失败

src/views/demand/consumer-behavior.vue

@@ -1772,6 +1772,12 @@ function downloadBuiltInFile(url, fileName) {
 }
 
 :deep(.questionnaire-editor-dialog .el-dialog),
+:deep(.questionnaire-preview-dialog .el-dialog) {
+    border-radius: 12px;
+    color: var(--student-text);
+    background: #ffffff;
+}
+
 /* ===== 结构化问卷预览弹窗 ===== */
 .questionnaire-compose-preview {
     max-height: 60vh;