Basics of html/css - Several vigilance points during the html code writing process (must read)

The vigilance point that this article wants to say has nothing to do with browser compatibility. It is mainly a summary of several small problems I encountered in the project. Although the problems are small, they are sometimes very troubled. Let me record it here. If there are such problems in the later stage, they will continue to be added here.

Under normal circumstances, you have the habit of wrapping lines and indenting when writing html code, such as