css background settings

CSS is a language used for web design, often used to control the style and appearance of web pages. The background is one of the most basic elements in a web page. You can flexibly set the background of a web page through CSS, bringing unlimited possibilities to website design. This article will introduce you to the basic knowledge and common usage of CSS background settings.

1. Introduction to CSS background

CSS background can not only be used to set the background of web pages, but can also be used to set the background of elements, such as DIV, BUTTON, etc. CSS background settings include various attributes such as color, picture, position, repetition, size, etc. By combining these attributes, you can create web pages of various styles.

2. CSS background color setting

The background color is the simplest setting in CSS and can be set through the background-color attribute. For example, to set the background color of a web page to white, you can add the following code to the style sheet:

body {
background-color: #ffffff;
}

where, #ffffff is the hexadecimal representation of white. In addition to hexadecimal, colors can also be expressed using RGB, RGBA, and HSL.

3. CSS background image settings

The background image is the most commonly used background setting in CSS and can be set through the background-image attribute. For example, to set the background of a web page to an image, add the following code to your style sheet:

body {
background-image: url('example.jpg');
}

Among them, url('example.jpg') represents the image path to be set. When setting a background image, you need to pay attention to the size and format of the background image file. It is best to choose an image of appropriate size and lossless compression.

4. CSS background position setting

The background position refers to the position of the background image within the element. It can be set through the background-position property. For example, place the image in the center of the web page background:

body {
background-image: url('example.jpg');
background-position: center;
}

A more general way is to use coordinate values, such as the following code to place the image at the top center of the web page background:

body {
background-image: url('example.jpg' );
background-position: center top;
}

5. CSS background repeat settings

When the image size is smaller than the element size, you need to use CSS background repeat settings to fill it the entire element. Can be set through the background-repeat attribute. For example, tile both horizontally and vertically:

body {
background-image: url('example.jpg');
background-repeat: repeat;
}

You can also set it to only repeat in the horizontal or vertical direction, or not to repeat.

6. CSS background size setting

The background-size attribute has been added to CSS3, which can be used to set the scaling method of the background image. For example, to scale the background image to a width of 100%:

body {
background-image: url('example.jpg');
background-size: 100% auto;
}

can also be used to set specific width and height values, or implement different scaling methods through keywords such as cover and contain.

7. CSS background transparency setting

Background transparency can be set through rgba color representation, where the alpha value is used to indicate the degree of transparency, with a value range of 0-1. For example, set the transparency of the web page background to 50%:

body {
background-color: rgba(255, 255, 255, 0.5);
}

In actual In applications, you can use other CSS properties, such as box-shadow, linear-gradient, etc., to make the background of the web page more vivid and vivid.

8. Summary

CSS background setting is an indispensable part of web design. Through the flexible combination of background color, picture, position, repetition, size and other attributes, it can be used for web design. Styles that bring a variety of styles. This article introduces the basic knowledge and common usage of CSS background settings to help readers better master and apply CSS technology.

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