how can I be sure that a website is responsive by only looking the code?. Would you say that if there is at least one @media in the css is responsive?

I found this looking for an answer 

> 
> The term responsive generally just indicates that the website uses CSS media selectors in order to modify its layout based upon device attributes. ([source](https://stackoverflow.com/questions/24527396/can-i-test-a-website-is-responsive-design?answertab=active#tab-top))
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My opinion is that @media doesn't implies responsiveness at 100% but it's a good indicator.

Let's say that the css developer start doing responsive, but leaves it empty. In that case, @media is detected but the website still not responsive.

```
@media screen and (min-width: 601px) {

}

```

What do you say? Is there any other alternative to say at 100% that a website is responsive?

Thanks for your time and your answers