What are the essential concepts of HTML and CSS that beginners should focus on when starting web development?

When starting web development, beginners should first learn HTML, the standard markup language that structures web pages using tags and attributes. The most crucial aspect is understanding semantic layout—using the right elements (header, main, footer) in appropriate places to create proper structure. With CSS, focus on the box model (margin, padding, borders, content), layout techniques like Flexbox and CSS Grid for positioning content, and responsive design to ensure websites look good across all devices. After mastering these fundamentals, practice by creating projects like landing pages to reinforce learning and apply these concepts practically.