Explore a captivating conference talk that delves into lesser-known aspects of CSS. Discover a series of obscure CSS fun facts, syntax gimmicks, quirks, and unexpected tricks. Learn about security vulnerabilities enabled by creative CSS usage. Gain insights from Mathias Bynens, a Belgian web standards expert and member of Opera Software's Developer Relations team. Uncover topics such as new !important best practices, CSS comments, valid HTML, CSS without HTML, classes and IDs in HTML, escaping CSS selectors, injection contexts, data theft from the DOM, IE's legacy document modes, CSS Expressions in IE, avoiding CSS expression vulnerabilities, and more. This 29-minute presentation from CSSconf EU 2014 offers a unique perspective on CSS, blending technical knowledge with intriguing trivia.