UTF-8 and style sheet problems

I wonder if you have encountered this problem: After the language encoding in Web. config is set to UTF-8, the style usage is abnormal, especially when the Chinese font is applied to the style.
I have never found a good solution to this problem. I generally set the language encoding in Web. config to gb2312. However, when lion's webhtmleditor is used, "?" appears in the content area where spaces exist. That is to say, webhtmleditor can only be used in UTF-8 encoding. (Disable the htmltagstoxhtml attribute, Which is htmltagstoxhtml = false, and webhtmleditor1.0 can be applied to the language code set to gb2312.). After I tried n methods, I suddenly remembered that sometimes some page files in some open-source projects outside China may be garbled. The solution is to open the notepad in the page file, save it as UTF-8 encoding format, for example:

"This is the same as the Style File". OK. The principle is not clear yet, and the effect is achieved. I wonder if you have encountered similar problems. How can we solve them?