Mobile first - Manage(HTML, CSS/SCSS, JS, Intersection Observer API)

Hello 👋 This is my 23th Frontendmentor challenge. This challenge is really tricky, At first I thought that It will easy landing page but I didn't especially in swipe testimonial spend a lot of time on that part. At first I want to use the swiper js for the testimonial swipe, but then again I want to learn more about JavaScript without using a library. I still don't know if I did right on mobile touch😅. My first time using the Intersection Observer API and It improved the page a lot. Some features on the page:

• Users will only be able to swipe the testimonial with Arrow Left, Arrow Right, A and D keyboard to swipe the testimonial.
• Added a touchevent touchstart event and when the user touch the left screen of testimonial it will swipe to left side and vise-versa.
• Added a Escape and touch overlay to exit the hamburger menu.
• First time using with Intersection Observer API, this API is detecting if an object has entered the viewport. When the user will not able to see the hero section the header will become sticky on top of the screen.

Feedback is welcome and appreciated!. Let me know of any issues you find. Thanks in advance.