Formally enter how to use c# and css to learn

1. This week, I have a preliminary understanding of c# and css.
2. The W3c World Wide Web Consortium is the most authoritative and influential technical standards organization in the field of Web technology. So far, W3c has released more than 200 Web technical standards and implementation guidelines that affect the comprehensive operation.
3. When I was learning to apply the C# language, I learned that css is the common use of html file format and beautifying the appearance. CSS is to change the format, background or color of the content written in html. In html, it consists of a large number of elements, and all the content structure in html is organized into pages by elements.
4. Text elements in html: h1~h6 title elements, p paragraph elements, q subparagraph citation elements, abbr display abbreviated content, cite citation elements for data documents, strong, b text bold elements. Among them, the b element is generally not used, because it can be implemented in css and the strong element will focus on reading in the voice reading browser.
5. The elements in html are composed of: h element, a element, empty element, heda element, body element and so on. The elements also have hierarchical division: there are parent-child, ancestor-descendant, and sibling elements.
6. In html5, < ! DOCTYBE html > is the type definition of the document, which is used to inform the browser which html version the current document is using. If there is no such document declaration, the browser will enter a weird mode when rendering the page.
7. There are two ways to refer to CSS documents in html, using relative paths and absolute paths.
8. There are 3 style sheets for referencing css to HTML: external style sheet, internal style sheet, and inline style sheet.