Box Model: Understand how elements are structured in CSS with properties like width, height, padding, border, and margin, which collectively define the space an element occupies on the page.
Selectors and Specificity: Master CSS selectors to efficiently target elements based on their attributes, classes, IDs, and relationships. Understand specificity to resolve conflicts when multiple styles apply to the same element.
Responsive Design: Learn techniques like media queries, flexbox, and grid layout to create responsive designs that adapt to different screen sizes and devices, ensuring a consistent user experience across platforms.