override.css does not work

Hello!
Yesterday I installed black&white template. I need to change some formattings. Usually I do this in override css file, but it doesn't work. This file is ignored completely, template.css is always ahead. What's wrong?
Thanks for help.
Best regards! Katrin

Hello!
I just notice the enable ovveride button in the template - so no need for help anymore.
Thanks!

Please make sure that option 'use override css' is enabled in your template settings (you will find it in developer's tab)