Chrome used to detect my app manifest and users were able to add to home screen as an app, not just a shortcut. But recently it’s not working. Chrome can’t now detect it.
I have solved it. I had unintentionally put the tag <head>... </head> in the script/meta tags in header box. Now removed and works perfectly as normal.
The loading icon is just my logo and a spinner (both SVG format). I put this loading icon at the bottom of everything (visible on page loaded) and also hide every other page as a default. And set the workflow 'when the page loaded, then animate (fade in) sign up page.
You can find and customize many nice & free SVG spinners here