diff --git a/web/app/components/datasets/create/step-two/index.tsx b/web/app/components/datasets/create/step-two/index.tsx
index 5dd7af33c9..95e2e766df 100644
--- a/web/app/components/datasets/create/step-two/index.tsx
+++ b/web/app/components/datasets/create/step-two/index.tsx
@@ -113,11 +113,11 @@ const defaultParentChildConfig: ParentChildConfig = {
   chunkForContext: 'paragraph',
   parent: {
     delimiter: '\\n\\n',
-    maxLength: 4000,
+    maxLength: 500,
   },
   child: {
     delimiter: '\\n\\n',
-    maxLength: 4000,
+    maxLength: 200,
   },
 }
 
@@ -922,7 +922,8 @@ const StepTwo = ({
               <Badge text='276 Estimated chunks' />
             </div>
           </PreviewHeader>}
-          className={cn(s.previewWrap, isMobile && s.isMobile, 'relative h-full overflow-y-scroll space-y-4')}
+          className={cn(s.previewWrap, isMobile && s.isMobile, 'relative h-full overflow-y-scroll')}
+          mainClassName='space-y-6'
         >
           {docForm === ChuckingMode.qa && estimate?.qa_preview && (
             estimate?.qa_preview.map(item => (
diff --git a/web/app/components/datasets/preview/container.tsx b/web/app/components/datasets/preview/container.tsx
index b5e7feaf9f..ffc2692524 100644
--- a/web/app/components/datasets/preview/container.tsx
+++ b/web/app/components/datasets/preview/container.tsx
@@ -4,10 +4,11 @@ import classNames from '@/utils/classnames'
 
 export type PreviewContainerProps = ComponentProps<'div'> & {
   header: ReactNode
+  mainClassName?: string
 }
 
 export const PreviewContainer: FC<PreviewContainerProps> = forwardRef((props, ref) => {
-  const { children, className, header, ...rest } = props
+  const { children, className, header, mainClassName, ...rest } = props
   return <div
     {...rest}
     ref={ref}
@@ -19,7 +20,7 @@ export const PreviewContainer: FC<PreviewContainerProps> = forwardRef((props, re
     <header className='py-4 pl-5 pr-3 border-b border-divider-subtle'>
       {header}
     </header>
-    <main className='py-5 px-6 w-full h-full'>
+    <main className={classNames('py-5 px-6 w-full h-full', mainClassName)}>
       {children}
     </main>
   </div>