Improve style

This PR aims to implement a new css file in the Innovare budle.

For this goal you have to:
- put your css file into `src/Innovare/MainBundle/Resources/public/css/`
- run the command `php app/console assets:install web --symlink`
- and add in your style block the following: `{{ asset('bundles/innovaremain/css/main.css') }}`