Why is responsive design not working?

Question

css

Here is the actual page: pyiio3k.bget.ru
I made a media request like:

@media screen and (max-width:768px){}

When I open a page in the browser and start to reduce the browser window, the adaptive layout works. In the case when I open the page through Iphone (MB and all other phones, etc.), media requests do not work. Tell me why?

Answer 1

100% missing meta tag

<meta name="viewport" content="width=device-width">

Answer 2

works, put yourself https://chrome.google.com/webstore/detail/mobilere...
awesome little thing