Why are my CSS3 media queries not working on mobile devices?

Don't forget to have the standard css declarations above the media query or the query won't work either.

.edcar_letter{
    font-size:180px;
}

@media screen and (max-width: 350px) {
    .edcar_letter{
        font-size:120px;
    }
}

All three of these were helpful tips, but it looks like I needed to add a meta tag:

<meta content="width=device-width, initial-scale=1" name="viewport" />

Now it seems to work in both Android (2.2) and iPhone all right...

I suspect the keyword only may be the issue here. I have no issues using media queries like this:

@media screen and (max-width: 480px) { }