Welcome to Maintaining a WordPress Site Using HTML & CSS: The Advanced Guide, the third of The Website Series of books. In Building a Website Using WordPress: The Beginner's Guide, you learned that WordPress is built on the LAMP (Linux, Apache, MySQL, Php) Stack and how to build your site from the ground up using all open source tools. In Making Your WordPress Site Awesome - The Intermediate Guide, you learned to enhance the site by employing accessibility, security, and engagement strategies. The goal of Maintaining a WordPress Site Using HTML & CSS: The Advanced Guide, is to move you from the role of WordPress web site designer to WordPress web site developer! The skills you have amassed as a WordPress site owner gives you the foundation required to go under the hood of the WordPress site and make some real magic. In Maintaining a WordPress Site Using HTML & CSS: The Advanced Guide, we will focus on the structure: HTML and the design elements: CSS of the WordPress site and the countless ways it can be manipulated to create a more robust experience. Many will ask: is another HTML/CSS book REALLY needed? My answer is of course, yes! To me, it is not the content but the style in which those who are new to the language need it presented. I find that a majority of students are not looking to code an entire site using only code. Most are using some GUI website tool to do the heavy lifting and want the ability to understand and manipulate the code when needed. Let's face it, as good as front-end applications are, having a working knowledge of the language the pages are created in is a major plus. HTML has had such a short but tumultuous history. The most difficult part of writing this book was balancing how much of HTML5 I should include for the absolute beginner of HTML and CSS and a veteran of WordPress. My goal is to supply a firm foundation to move forward and use HTML and CSS to build and maintain your WordPress sites, but it is tempting to take you down memory lane and include deprecated tags, and how DOCTYPES have evolved. You will notice that I do include information from older versions of the language for reference.