English language has a number of popular manuals of style. There's Chicago Manual of Style, Elements of Style etc.
Do you know any such resource for the Polish language?
After a considerable bit of research, I came across this on the Polish language Wikipedia page on proofreading (Korekta tekstu).
From the Google-provided broken English translation:
And in the original Polish:
So the closest thing to an accepted and universal "manual of style" in the Polish language (according to Wikipedia) is the Książka Kultura języka polskiego (The book of Polish Language and Culture) by Hanna Jadacka (T.1.: Inflection, word formation, syntax), Andrzej Markowski (T.2.: Theory, Lexical Issues), and Thomas Karpowicz (T.3.: Pronunciation, spelling, punctuation). And if there are issues of preferred writing style, each publication uses its own internal reference guides.
Other Style Guides for the Polish Language
In addition to The book of Polish Language and Culture (which appears to be a general reference of grammar, syntax and punctuation), there are other international style guides which are provide rules for the proper translation of laws, regulations and business practices into several languages, including Polish.
Another is the International Standards Organization (ISO) which provides several international standards for businesses and government. There are many, many different documents on the proper use of style in several international languages (including Polish) that are dependent on the situation (such as ISO 31 for quantities and units or ISO 5966 for the presentation of scientific and technical reports).
Tangentially related, the European Committee for Standardization (CEN) also provides a certification called EN-15038 which is an international standard for translation service providers that ensures proper translation into various languages. The PKN EN 15038 is the version specifically for the Polish Language. You have to pay CEN to find out exactly what is entailed with being EN-15038 certified in Polish, but you can get some idea here.
I don't believe that there is a generic manual of style for the Polish language. Different universities and government bodies may publish style manuals for specific publications (such as official government documents, or paper submission), but nothing general.
It's also worth noting that there are several dialects of Polish in use, which may influence the writing style of the author in ways that won't be compatible with a common style-document