Hi,
That file doesn't exist because it's generated dynamically by the extension jchoptimize from other CSS files.
When you want to customize the CSS on your website, you first need to disable the extensions like this one because otherwise, you can't really know where the CSS comes from.
So I can't say exactly where that CSS has to be removed but :
1. That's not related to HikaShop and since it's a global CSS, it probably comes from your template
2. Here is a tutorial on how to use the web inspector of your browser to find what CSS applies to what element so that you can easily find where to do the change once you disable jchoptimize:
blog.thewcc.com/a-web-inspector-tutorial...ront-end-developers/