What is css abbreviation?

css is the abbreviation of Cascading Style Sheets. It is a computer language used to express file styles such as HTML or XML. It is mainly used to design the style of web pages and beautify web pages. It can not only statically It can be used to modify web pages, and can also cooperate with various scripting languages ​​to dynamically format various elements of web pages.

The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.

CSS refers to Cascading Style Sheets (Cascading Style Sheets)

• is an application used to express HTML (Standard Common Markup Language) or XML (Standard Common Markup Language) A computer language that documents styles such as Universal Markup Language
  

• # Styles define how HTML elements are displayed

• Styles are typically stored In the style sheet

• Adding styles to HTML 4.0 is to solve the problem of separation of content and presentation

• External style sheets can be extremely Greatly improve work efficiency

• External style sheets are usually stored in CSS files

• ##Multiple style definitions can be cascaded into one

• Styles provide pixel-precise control over the layout of element positions on web pages

CSS helps achieve responsible web design. CSS has a huge impact on how developers build Web sites, and the impact may be endless. Moving most or even all of the presentation information of a web page out of (X)HTML files and keeping them in a style sheet has many advantages, such as reducing file size, saving network bandwidth, and ease of maintenance. In addition, the separation of the site's performance information and core content allows site designers to make various modifications to the entire site in a short period of time.

CSS simplifies the format code of the web page, and the external style sheet will also be saved in the cache by the browser, speeding up the download and display speed, and also reducing the amount of code that needs to be uploaded (because repeated formatting will is saved only once). As long as you modify the CSs style sheet file that saves the website format, you can change the style and characteristics of the entire site. It is particularly useful when modifying a site with a large number of pages. This avoids modification of web pages one by one and greatly reduces the workload.

CSS Style

CSS rules consist of two main parts: the selector, and one or more declarations:

The selector is usually the HTML element you need to change the style of.

Each statement consists of an attribute and a value.

The property is the style attribute you wish to set. Each attribute has a value. Properties and values ​​are separated by colons.

Example:

p {color:red;text-align:center;}

Applying the same style to multiple pages

Usually saved in an external independent .CSS file (this file does not belong to any page file) can use the same CSS style sheet in multiple pages. By referencing the .CSS file in any page file, you can set up multiple pages with a consistent style.

Style cascading

Style cascading is to set the same style multiple times on an element, which will use the last attribute value set.

Style cascading order

When multiple styles are defined for the same HTML element, which style should be used?

Generally speaking, all styles will be cascaded in a new virtual style sheet according to the following rules, with number 4 having the highest priority.

• Browser default settings

• External style sheet

• Internal style sheet (located in < ;head> tag)

• Inline styles (inside HTML elements)

Therefore, inline styles (inside HTML elements) Has the highest precedence, which means it will take precedence over style declarations in tags, in external style sheets, or in the browser (the default).

(Learning video sharing:

css video tutorial)

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