Full width background image issues (on row widget) on mobile device

Hi there,

I created a background image in the middle of the page by doing the following:

1. Add a row
2. Edit the row
3. Go to “Design Section” and add a background image
4. Change the “layout” to “full width stretched”

It works in the desktop site, but in mobile device, the background image won’t resize. The link to my site is as follows:

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Can anyone assist?

Thanks!