You can create it thru FTP. However, if you really don't know how to create file on FTP (this is very basic thing), please contact with your web developer because you may do more harm than good.
Ok, thanks. So as you can see on the following screenshot https://snag.gy/eQY0xZ.jpg there is css that should be copied. But in reference to your 2nd question, you can not load it as needed.
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if you don't see such file, then just create it yourself.