How to modify css

CSS (Cascading Style Sheets) is an indispensable part of Web page design. It is used to style and layout HTML elements. In actual applications, you may often need to modify CSS files to better control page styles. In this article, we will discuss how to modify CSS files.

1. Understand the CSS file structure

Before you start modifying the CSS file, you first need to understand the structure of the CSS file. CSS files usually consist of three main parts: selectors, properties, and property values. The selector specifies the element to which the style will be applied, the attribute sets the style properties of the element (such as color, font, border, etc.), and the attribute value specifies the specific value of each attribute.

The following is a simple CSS example:

h1 {
  color: red;
  font-size: 24px;
  text-align: center;
}

In this example, h1 is the selector, color, font- size and text-align are attributes, red, 24px and center are the attribute values ​​of the corresponding attributes.

2. Use browser developer tools for real-time debugging

Before modifying the CSS file, we'd better use the browser developer tools for real-time debugging for better Understand which elements in the current page need to be style modified. Use browser developer tools to easily view information such as internal styles and calculated styles of elements, and preview the effects of style changes in real time.

To open the developer tools in Google Chrome: right-click on any element on the page and select "Inspect", or press F12 to open the developer tools. In the Elements panel in the lower left corner of the tool window, we can see the tree structure of all elements on the page, and in the Styles panel on the right, we can view and modify the style properties of the elements.

3. Modify CSS files

After we determine the elements and style attributes that need to be modified, we can start editing the CSS files. If this is your first time modifying CSS, you can try following these steps:

• Open the CSS file. If you open the CSS file in an editor, you can use the Sources panel in the developer tools to find the corresponding CSS file.
• Confirm the selector that needs to be modified. To find the selector that needs to be modified in the editor, you can use the search function (Ctrl/Cmd F) to quickly find it.
• Modify attributes and attribute values. After determining the required modifications, modify the corresponding properties and property values ​​directly in the CSS file. If you're unsure about a new property value, you can preview and debug it in real time in the developer tools.
• Save the CSS file. Once the modifications are complete, save the changes to a CSS file.

4. Enhance the readability of style code

In order to avoid problems during subsequent maintenance and modification, it is necessary to maintain the readability of style code. This can be achieved by following some simple rules:

• Indent the code according to certain rules, keep the code with corresponding spacing to the left or right, and enhance the beauty of code layout.
• Use comments to describe code blocks to make the code easier to read during subsequent modifications and maintenance.
• Follow the naming convention and make the class name and ID name in the code related to each other, which can improve the readability of the code.

In practice, there are a few other techniques that can be applied to enhance readability, but these above should suffice.

In short, if you want to modify the CSS file, you need to first understand the CSS file structure, and then use the browser developer tools for real-time debugging. After the modification is completed, the readability of the style code must be enhanced to facilitate future maintenance and It's easier to understand the code when making changes.

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