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My website uses random words for CSS classes. For example: gruig.
Now I'm little scared that this might somehow lower our Google rankings. Will it?
Google says nothing about that. So it's ok. But, you should minify your css because it's good practice to optimize your CSS code to make your website faster by decreasing the file size.
No search engine cares one whit about your class names and such things are given no SEO consideration in any way, shape or form. They serve no purpose as far as content goes. They mean nothing to the end user.
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