To learn this series of tutorials, you need to have a certain basic knowledge of HTML and CSS, which means you have made web pages before and know how to use table layout. If you have just started learning web page production and don't know what table layout, html and css are, it is recommended that you recharge your batteries first, otherwise you will have a hard time learning this tutorial or you will not understand it at all.
Due to time constraints, this tutorial only explains some practical knowledge, allowing you to move from the original table layout to the web standard (div css) layout, and use web standards to create common pages, which also achieves the purpose of this tutorial.
This tutorial is mostly explained step by step in the form of examples. The key points or difficulties involved in the examples will be explained, and the concepts will be less explained. Because concepts are difficult to explain clearly, or even if you explain them clearly, you may not be able to understand them, and even if you understand them, you may not be able to understand them. So I leave the concept to you to study in depth later.​