The Least You Need to Know
• HTML tags identify the nature of different elements, whereas CSS applies the formatting to those elements.
• To properly use HTML paired tags, insert the opening tag at the beginning of the element and the closing tag at the end.
• XHTML is simply HTML with a stricter set of rules to follow.
• By formatting with CSS, you can make changes in a single style sheet that change the formatting for all the pages on your site.
• HTML5 and CSS3 introduce plenty of new features, but web browsers may be slow to support the new features.