Thank you, your advice regarding the mobile menu helped me to solve the issue!
Unfortunately, if I add a bigger image for the slider (I tried same then in event star demo has: 1280×610), it will display too high image on the desktop, all feature information section will be out of the viewport but mobile version is still a bit out of proportion and slider buttons are also out of the view partly. What would be the perfect dimension for the slider from theme perspective? And would it be possible to set a mobile version slider size in css?