CSS is a ruleset for telling the browser how to display the HTML formatted contents. Although it’s not a programming language like HTML and the rest but it can be a lot more powerful.
PHP code is commonly used for server side to interact with the file system and database and output HTML. A web developer would know that the “back-end” is where the real programming takes place and there lies the power of PHP. Obtaining of user’s information is being done using PHP. Example is, the comment section on YouTube rely on PHP to obtain display names and comments from the database. You can also use python, Perl, .NET and a handful of other languages/framework to do these but PHP has been here for a long time and would continue to be while MySQL is a database where user’s information are being stored.
At GIIT Web Development classes, we tutor you on each web frameworks above in depth and we make you put your skills into test by giving you a project you would be working with in-line with everything you’re going to being taught.