How to add a custom css?

What is the best way to add custom css to openerp 7 without modifying any original file of openerp?

Just create a module and add your css file in as described in the documentation.

     'name': "CSS Example",
     'description': "new css example",
     'category': 'Generic Modules/Others',
     'depends': ['web'],
     'data': [],
     'css': ['static/src/css/my_css.css'],

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