What are css style attributes

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Introduction

Cascading Style Sheets (English full name: Cascading Style Sheets) is an application used to express HTML (an application of Standard Generalized Markup Language) or XML (a subtype of Standard Generalized Markup Language). set) and other file styles of computer languages. CSS can not only statically modify web pages, but can also cooperate with various scripting languages ​​to dynamically format various elements of web pages.

CSS can perform pixel-level precise control over the layout of element positions in web pages, supports almost all font size styles, and has the ability to edit web page objects and model styles.

Language Features

CSS provides a style description for the HTML markup language and defines the display mode of the elements. CSS is a breakthrough in the field of web design. It can be used to modify a small style to update all page elements related to it.

Generally speaking, CSS has the following characteristics:

Rich style definition

CSS provides rich document style appearance, as well as setting text and The ability of the background attribute; allows you to create a border for any element, as well as the distance between the element border and other elements, and the distance between the element border and the element content; allows you to freely change the capitalization, decoration, and other page effects of text.

Easy to use and modify

CSS can define the style in the style attribute of the HTML element, or in the header part of the HTML document, or in the Styles are declared in a special CSS file for reference in HTML pages. In short, CSS style sheets can store and manage all style declarations in a unified manner.

In addition, elements of the same style can be classified and defined using the same style, you can also apply a certain style to all HTML tags with the same name, or you can assign a CSS style to a certain in page elements. If we want to modify the style, we only need to find the corresponding style statement in the style list and modify it.

Multi-page application

CSS style sheets can be stored in a separate CSS file, so that we can use the same CSS style sheet in multiple pages. Theoretically, CSS style sheets do not belong to any page file and can be referenced in any page file. In this way, the styles of multiple pages can be unified.

Cascading

Simply put, cascading is to set the same style multiple times on an element, which will use the last attribute value set. For example, if you use the same set of CSS style sheets for multiple pages in a site, and if you want to use other styles for some elements in some pages, you can define a separate style sheet for these styles and apply them to the page. These styles defined later will override the previous style settings, and what you see in the browser will be the style effect set last.

Page Compression

In websites that use HTML to define page effects, a large number or repeated tables and font elements are often required to form text styles of various specifications. In this way The consequence is that a large number of HTML tags will be generated, thereby increasing the size of the page file. Putting the style declaration separately in the CSS style sheet can greatly reduce the size of the page, so the time spent loading the page will also be greatly reduced. In addition, the reuse of CSS style sheets reduces the size of the page to a greater extent and reduces the download time.

How it works

CSS is a language that defines style structures such as fonts, colors, positions, etc., and is used to describe elements on web pages. The way information is formatted and realistic. CSS styles can be stored directly in HTML web pages or in separate style sheet files. Either way, a style sheet contains rules for applying styles to elements of a specified type. For external use, style sheet rules are placed in an external style sheet document with the file extension _css.

Style rules are formatting instructions that can be applied to elements on a web page, such as paragraphs of text or links. A style rule consists of one or more style attributes and their values. Internal style sheets are placed directly in the web page, external style sheets are saved in separate documents, and the web page links to the external style sheets through a special tag.

The "cascading" in the name CSS refers to the way style sheet rules are applied to elements of an HTML document. Specifically, the styles in a CSS stylesheet form a hierarchy, with more specific styles overriding common styles. The priority of style rules is determined by CSS based on this hierarchy, thereby achieving a cascading effect.

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