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How to write css style

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Release： 2023-05-27 11:02:37

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CSS (Cascading Style Sheets) is a language used to describe the style of web pages. CSS provides a wealth of style attributes that allow us to more flexibly control the style of web pages. In this article, I will share some CSS style writing methods to help you better master style control.

1. Inline style

Inline style is to set the style attribute in the style attribute of the HTML tag, as shown below:

<p style="color: red;">这是一段红色的文字。</p>

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This way of writing is very intuitive, but Frequent use is not recommended as it makes the HTML code verbose and difficult to maintain.

2. Embedded style

Embedded style uses style tags at the head of the HTML file and writes CSS code in it. As shown below:

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>嵌入式样式</title>
  <style type="text/css">
    p {
      color: red;
    }
  </style>
</head>
<body>
  <p>这是一段红色的文字。</p>
</body>
</html>

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This way of writing is better than inline style, because it can put all the style code in the head and reduce the amount of code in the page. However, if multiple HTML files need to use the same style, the style code needs to be copied again, resulting in increased maintenance costs.

3. External style

External style puts the style code in a separate CSS file and then introduces it in the HTML file. As shown below:

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>外部样式</title>
  <link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
  <p>这是一段蓝色的文字。</p>
</body>
</html>

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The style code is placed in the style file style.css, as shown below:

p {
  color: blue;
}

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This way of writing is the best, because it separates the style code and HTML code, reducing Redundant HTML code is eliminated, making the entire page layout clearer. At the same time, if multiple HTML files need to use this style, you only need to modify the style file, and all pages that reference this style will be automatically updated.

In addition, there are some CSS style writing methods that are also very common in actual development:

4. Selector

The selector is used to specify the application style. HTML element. CSS supports a variety of selectors, common ones are:

Element selector: selects HTML elements of a specified type.

p {
  color: red;
}

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ID selector: used to select HTML elements with a specific ID.

#myId {
  color: blue;
}

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Class selector: used to select HTML elements with specific class names.

.myClass {
  color: green;
}

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Attribute selector: Select HTML elements with specific attributes.

input[type="text"] {
  border: 1px solid red;
}

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5. Style attributes

Style attributes are used to describe the style of elements. CSS supports many style attributes, here are just a few common ones:

color: text color.

p {
  color: red;
}

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font-size: Font size.

p {
  font-size: 14px;
}

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font-family: Font type.

p {
  font-family: Arial, sans-serif;
}

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background-color: background color.

p {
  background-color: yellow;
}

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border: border.

p {
  border: 1px solid black;
}

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margin: Margin.

p {
  margin: 10px;
}

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padding: Padding.

p {
  padding: 5px;
}

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6. Pseudo-classes and pseudo-elements

Pseudo-classes and pseudo-elements are used to add styles to specific states or parts of elements.

Pseudo class: used to describe a special state of an element.

a:hover {
  color: red;
}

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Pseudo element: used to describe a special part of the element.

p::first-line {
  font-weight: bold;
}

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The above is the common way to write CSS styles. Of course, in actual development, in many cases different styles need to be written in different style sheets (such as print styles, mobile styles, etc.), and the relationship between these style sheets also needs to be paid attention to. At the same time, the performance issues of CSS styles also need to be considered to avoid excessive nesting and overly complex selectors. Hope this article is helpful to you.

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