أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
You should always use a style sheet, because it allows you to quickly and easily change the entire appearance and layout of your site. If you embed the style information in the HTML directly, you have to work a lot harder if something needs to change; with a style sheet, you simply change the CSS file in a single location, and the change becomes global everywhere that style sheet is used.
Thank you for the question, but it is not clear what you mean by staling in html. Can you give an example?