Implement css

Implementing CSS: Understand basic concepts and master core skills

CSS (Cascading Style Sheets) is a language used to control the style of web pages. Together with HTML, it forms the basis of web page production. The role of CSS is to layout and beautify the content in HTML documents, making the page more beautiful, clear, and easy to read and operate. For front-end developers, the mastery of CSS directly affects the efficiency of work and the user experience of the website. This article will introduce the core concepts and techniques of CSS to help readers better understand and master CSS.

1. Basic concepts

1. Selector

In CSS, a selector is used to select and style HTML elements. model. Common selectors include tag selectors, ID selectors, class selectors, attribute selectors, etc.

Tag selector: Select specified HTML tags, such as p, h1, div, etc.

ID selector: Select elements based on the id attribute of HTML elements, such as #header.

Class selector: Select elements based on the class attribute of HTML elements, such as .dropdown.

Attribute selector: Select elements based on the value of the element's attributes or the status of an attribute.

2. Style Rules

Each style rule consists of a selector and a set of declarations. For example:

p {

color: red;
font-size: 16px;

}

This rule selects all p tags in the web page and sets their color and font size.

Declarations in style rules consist of attributes and values.

3. Box model

In web page layout, each HTML element can be regarded as a rectangular box. The box consists of four parts, including content area, padding, border and margin.

4. Cascading Style Sheets

Cascading Style Sheets (Cascading Style Sheets) are a style sheet formed by multiple style sheets cascading in a specific order. When multiple style rules are applied to the same element, the CSS engine will determine which styles will be applied in a certain priority order.

2. Core skills

1. Inheritance

CSS inheritance means that when the style of an element is not specified, it will be inherited from its parent element. The process of inheriting styles. For example:

body {

font-size: 16px;

}

p {

color: red;

}

In the above style rules, the body element The font size is 16px without specifically specifying the font size of the p element. Therefore, the p element will inherit the font size of the body element. Writing code like this can simplify writing CSS rules.

2. Selector weight

Selector weight is used to determine which styles will ultimately be applied when multiple style rules apply to an element at the same time.

The weight of the selector consists of three parts, namely the number of elements, classes and IDs.

The element selector has a weight of 1, the class selector has a weight of 10, and the ID selector has a weight of 100.

For example:

p {

color: red;

}

p.warning {

color: yellow;

}

header {

color: blue;

}

In the above style rules, the weight of the p element selector is 1, the weight of the class selector .warning is 10, and the weight of the ID selector #header is 100. Therefore, for a p element, its final color will be yellow.

3. Box Model

Mastering the basic concepts of the box model can help developers better manage page layout and style.

For example, you can use the padding and border attributes to set the padding and border of an element, as follows:

.box {

padding: 20px;
border: 1px solid #ccc;

}

4. Animation effects

CSS provides various animation effects to enhance user experience, such as transition, rotation, zoom in and out, etc.

You can use the transition and animation attributes to add transition and animation effects to elements, as shown below:

.box {

transition: all 0.3s ease-in-out;

}

.box :hover {

transform: scale(1.2);

}

In the above style rules, when the mouse hovers over the .box element, the size of the element will be enlarged by 1.2 times, accompanied by a 0.3 second delay. Transition effects.

Summary

CSS is an essential part of web page production. Understanding the basic concepts of CSS and mastering core skills can help front-end developers better manage styles and page layouts, and improve work efficiency and user experience. I hope this article can help readers better understand and learn CSS.

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