The article delves into the complexities of CSS, highlighting that while CSS may seem straightforward, its underlying concepts require a deeper understanding to avoid common pitfalls. It critiques the prevalent educational approach that emphasizes memorizing CSS rules without focusing on core concepts, which often leads to unexpected behaviors, especially for those accustomed to imperative programming languages. The article explores five key CSS concepts: block formatting contexts, grid and Flexbox behaviors, the cascade, specificity, the box model, and stacking contexts, explaining how each affects the layout and style of web pages. It emphasizes the importance of understanding these concepts to improve CSS proficiency, suggesting that developers should focus on theory and practice rather than quick-result tutorials. The article also underscores the influence of the cascade and specificity in determining how CSS rules are applied, advocating for the mastery of these elements to create scalable and maintainable stylesheets.