Trouble Viewing Site On Mobile

Site URL: https://www.debbiemarkswellness.com/

I'm having a hard time wrapping my head around this... I spent some time today optimizing my site for mobile, reducing image sizes, styling the nav menu, adding a logo to the nav menu... Everything looks ok when I'm holding my mobile phone upright/in portrait. It's when I turn my phone sideways/landscape, that things get really funky. The browser window no longer fills the frame, there's a left right scroll indicator, it just looks really off and I wonder if I made an error in my custom code. Photo below. Also, and maybe even more concerning, when I flip my device back to portrait/upright, the browser doesn't snap back to full frame as seen in the photo below. 

Any advice would be helpful! 

PW: BEWELL

Try adding this to Home > Design > Custom CSS

html, body {
	overflow-x: hidden;
}

Hmm, that didn't do anything @tuanphan, BUT I'm having the same issue with other websites, so it might be my device and not the website.