Whenever we talk about learn web designing, the first website is w3schools because all the tutorials are complete and updates on this website so this is the best place to learn. You can also test your codes in live editors in this website.
Although this is the best site for PHP and web development you can also learn all tools of web designing here. This site also has some Video Tutorials which are extremely helpful because you can learn more by watching live projects.
This is also a very good website, you can learn complete HTML and CSS within 30 days. You can learn here Photoshop too in a professional way for Free.
This is also one of the best websites to learn web designing. It resembles w3schools. You can find live examples and projects with their source codes and explanations with Tips here.