How to use css3

CSS (Cascading Style Sheets) is a language used to style web page elements. It was released back in 1996, and after years of development and improvements, it has now been released to CSS3.

CSS3 provides developers with many new functions and features, such as animation effects, control of text appearance and layout, and more. In this article, we’ll take a closer look at how to use CSS3.

1. CSS3 Selectors

CSS3 introduces many new selectors, allowing developers to more accurately select elements to apply styles. Here are some common selectors:

1. Element selector: Select elements by HTML element name. For example: p{}.
2. Class selector: Select elements by the value of the HTML class attribute. For example: .classname{}.
3. ID selector: Select elements by the value of the HTML id attribute. For example: #idname{}.
4. Attribute selector: Select elements through the attribute values ​​of HTML elements. For example: [attr=value]{}.
5. Pseudo-class selector: Select elements by their status or position. For example: :hover{}, :nth-child(){}.
6. Pseudo element selector: used to select a specific part of an element, such as::after{}, ::before{}.

2. CSS3 animation

CSS3 animation is a method of making elements change dynamically on the page. It uses the new @keyframes rule and some new properties such as animation-name, animation-duration and animation-timing-function.

Here is a simple example:

/* 定义动画 */
@keyframes mymove {
    from {left: 0px;}
    to {left: 200px;}
}

/* 应用动画 */
div {
    animation-name: mymove;
    animation-duration: 5s;
}

This example will move a div element on the page 200 pixels along the x-axis, taking 5 seconds to complete the animation.

3. CSS3 Box Model

The box model means that when positioning elements on a web page, the element is regarded as a "box", including the content area, padding, border and margin. . CSS3 introduces a new box model that allows more precise control over the size and position of page elements. It adds the width of the border and padding to the width and height of the element itself.

The following is an example:

/* 使用新的盒模型 */
div {
    box-sizing: border-box;
    width: 50%;
    padding: 20px;
    border: 1px solid black;
}

This example will make the div on the page set the width to 50% of the parent element, including the content area, padding, and borders. Without the new box model, borders and padding would increase the width and height of the element itself.

4. CSS3 Fonts

Using CSS3, you can more precisely control the appearance and layout of your text. Here are some new properties:

1. font-face: Used to define a custom font loaded for the web page.
2. text-shadow: Used to add text shadow.
3. text-overflow: Used to control what happens when text overflows an element.
4. word-wrap: Used to control how long words wrap in text.

Here are some examples:

/* 定义字体 */
@font-face {
    font-family: "MyFont";
    src: url("myfont.ttf");
}

/* 应用字体 */
body {
    font-family: "MyFont";
}

/* 添加文本阴影 */
h1 {
    text-shadow: 2px 2px #000000;
}

/* 控制文本溢出 */
p {
    text-overflow: ellipsis;
    white-space: nowrap;
    overflow: hidden;
}

/* 控制长单词的换行方式 */
p2 {
    word-wrap: break-word;
}

5. CSS3 media queries

Media queries are a method of using CSS3 that can be adjusted based on the size of the browser window or Other device properties to apply different styles. This allows the website to better adapt to different monitor sizes and devices.

Here is an example:

/* 当浏览器窗口小于 600 像素时应用不同的样式 */
@media only screen and (max-width: 600px) {
    body {
        background-color: lightblue;
    }
}

This example will change the background color of the page to light blue when the browser window is smaller than 600 pixels.

Summary:

CSS3 introduces many new functions and features that allow developers to more easily control the style and layout of web page elements. This article introduces some commonly used CSS3 features, including selectors, animations, box models, fonts, and media queries. Hopefully this article will help readers better understand how to use CSS3.

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