A massive, 500+ page crowd-sourced PDF that covers everything from basic syntax to advanced Flexbox and Grid layouts.
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Finding a quality CSS textbook (uchebnik) in PDF format is a great way to master web styling. While "uchebnik po CSS" refers to general Russian-language resources, many of the most comprehensive and widely used guides are available globally as free or open-source PDFs.
A classic, step-by-step beginner's guide that breaks down web design into manageable 1-hour lessons.
A peer-reviewed academic overview of core CSS concepts, ideal for students. New Perspectives on HTML 5 and CSS: Comprehensive - Karbust
A detailed textbook covering the integration of HTML structure with CSS presentation.