custom @media query

Hello,
but the custom media queries in Page builder CK do not work?
I tried creating a custom.css in the template protostar but not working.

Can you help me?
I apologize for my English, I'm helping with google translate. :S
Thanks so much.

Hi
Please explain me what you want to do, and give me the url to see the problem
CEd

The site is in testing on the local server with XAMPP, I can not give you a url.
Basically I want to give a specific size for different screens for some images.

This is not possible.

Thanks so much!

you can do what you want using your own CSS code and mediaqueries. But this is in my mind out of the scope of page builder, and without any url I will not be able to tell you what could be wrong ...

Essentially the heading image has a max-width: 600px.

I would like to set a max-width: 300px to the mobile device via @media queries but not working.

Use a file custom.css in protostar.

I hope I explained.

Thanks so much!

ok I understand, but as said if you don't put your website online I can not do anything to debug. You shall put your website on a temporary server
Else you can also debug yourself using Firebug