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Solution to CSS styles not displaying properly

王林

Release： 2024-02-24 13:18:08

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Solution to CSS styles not displaying properly

What to do if CSS cannot be displayed, you need specific code examples

CSS (Cascading Style Sheets) is a markup language used to describe the style of web page elements. Define different style rules to control the layout, color, font and other appearance effects of the web page. However, sometimes we encounter the problem that CSS cannot be displayed, causing the web page to fail to render the set style properly. This article will introduce some common CSS display problems and provide specific code examples to solve them.

Error in introducing CSS files

Use the tag in the head (

) tag to introduce external CSS files. If the reference path is incorrect, The CSS file will not load. Here is a sample code that brings in an external CSS file:

<head>
  <link rel="stylesheet" type="text/css" href="styles.css">
</head>

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Make sure the file path in the href attribute is correct and that the file name or extension is spelled correctly.

CSS Selector Error

CSS selectors are used to select HTML elements and apply styles to them. If the selector is written incorrectly, the style will not be applied to the target element. Here are some common CSS selector problems:

Element selector error: Using the wrong element name for selection. For example, div is written as Div;
class selector error: using the wrong class name for selection, or not adding the corresponding tag to the target element in HTML Class name;
ID selector error: Use the wrong ID name for selection, or do not add the corresponding ID name to the target element in HTML.

Correct selector example:

/* 元素选择器 */
div {
  color: red;
}

/* 类选择器 */
.className {
  color: blue;
}

/* ID选择器 */
#idName {
  color: green;
}

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Style priority issue

CSS styles have different priorities when multiple styles When rules apply to the same element at the same time, the style with higher priority will override the style with lower priority. The following is the order of priority of styles from high to low:

!important: Styles marked with !important have the highest priority and can override other styles;
Inline styles : The style defined directly in the style attribute of the HTML tag has the second highest priority;
ID selector: The ID selector has a higher priority than the class selector and element selector;
Class selector and attribute selector: Class selector and attribute selector have the same priority;
Element selector, pseudo-element selector and pseudo-class selector: These selectors have the lowest priority.

When applying a style, make sure that the priority of the style is correct and that no other styles are overriding the target style.

CSS property spelling errors

CSS property spelling errors are one of the common reasons why CSS does not display. The following are some common CSS property spelling errors:

Writing less, more, or incorrectly writing certain characters;
The property name is case-incorrect, and CSS property names are size-sensitive Written;
The attribute value quotes are missing or do not match;
The attribute value is wrong, for example, the length value is written as a percentage.

Make sure that CSS properties are spelled correctly and that property values and quotes are used correctly.

Sample code:

div {
  background-color: red;
  width: 100px;
  height: 200px;
  border: 1px solid black;
}

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Selector optimization problem

When writing CSS, in order to improve efficiency and flexibility, you can use selector optimization to Reduce the number and complexity of selectors. If you use complex selectors too much, it will increase parsing and rendering time and cause display problems. The following are some suggestions for selector optimization:

Avoid using tag selectors, try to use class selectors and ID selectors;
Avoid using descendant selectors and sibling selectors, Try to use parent elements to limit the selector scope;
Avoid using universal selectors and try to use specific selectors;
Avoid using attribute selectors and pseudo-class selectors unless necessary ;
Avoid selectors with too deep levels and limit the number of levels of selectors.

By optimizing the selector, you can improve rendering performance and solve CSS display problems.

Summary:

The above are some common CSS display problems and corresponding solutions and code examples. When you encounter problems with CSS display, you can check the introduction of CSS files, the correctness of selectors, the priority of styles, the spelling of attributes, and the optimization of selectors. Through step-by-step troubleshooting and debugging, problems can be quickly found and solved.

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