How to make vertical epub e-books

The method of modifying punctuation marks is a reference practice of centering all punctuation marks in a paragraph. Replace punctuation marks in the article with regular expressions, add all punctuation marks in the article as "span", and define the font of punctuation marks as "Song T", so that punctuation marks are called traditional Song font, which can be distinguished from the font of the text and the punctuation marks can be centered. Disadvantages: the code will be cumbersome and not concise and beautiful. When there are a large number of punctuation marks, the time for editing, processing and verifying EPUB files will be slow, and it may even lead to Sigil jam. Imitate ancient books, turn from right to left, and edit in content.opf