FAQ accordion using Semantic HTML, CSS and jQuery

Hello, frontend Mentor Community. This is my solution to the FAQ accordion card challenge. It was a bit of a challenge since I'm fairly new to jQuery, but it was fun working on this.

A few questions:

• What exactly does 'HTML landmarks' mean?
• There is this illustration box on the desktop view that displays well on my device's local server, but disappeared in the live site and won't even show in my screenshot (check my solution screenshot). I've tried all sorts but can neither find the problem nor think of a solution.

I'll be very grateful for any help with this and also for any kind of feedback on my code and challenge solution.