Cannot find the way to increase theme width

Hi there,
Is anybody there to help me find the way to increase the width of my theme. I checked entirely style.css for main or # wrap etc but could’t find the way to increase it kindly do let me know if someone have the answer where do i need to make changes here are the codings as well. Just point out please because i m fully tired by checking .
Will be thanksful

Regards

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