Not Responsive

Hello, I have a problem with the responsivity. On mobile phone the site isn’t responsive.
How can I fix this?

I tried this code, which I found on forum:
@media (max-width:480px) {
.header_section {
width: 160%;
height: 300px;
}
}

But it works only for header.

The page I need help with: [log in to see the link]