Webflow Designer and Live Preview Stuttering

I’m trying the Webflow 101 course and following through the content in same way. But my Designer is stuttering whenever I’m scrolling up or down to move to different sections. Even the live preview and shared link preview also stuttering the page. Don’t know what’s happening! Any expert help please??

Here is my site Read-Only: LINK
(how to share your site Read-Only link)