Discuss the reasons and solutions why CSS does not inherit parent class styles

CSS does not inherit parent class styles

CSS is one of the important technologies in front-end development. It can control the style and layout of web pages, making our web pages more beautiful and easier to read. In CSS, an important concept is "inheritance", which means that child elements will automatically inherit the style of the parent element. However, in some cases, we may find that CSS styles are not inherited into child elements. Today we will explore the reasons and solutions for CSS not inheriting parent class styles.

1. CSS inheritance rules

In CSS, when an element does not specify the value of a certain attribute, it will inherit this attribute from its parent element. value. This rule is limited in that it only applies to certain properties. Specifically, the following properties can be inherited by child elements:

color, font-family, font-size, font-style, font-weight, letter-spacing, line-height, text-align, text-indent , text-transform, visibility, word-spacing

Some CSS properties and elements themselves will not be inherited, such as:

display, margin, padding, border, background, height, width, position, top, left, right, bottom, float, clear

The reason why these properties are not inherited by child elements is that if they are inherited, it may cause layout confusion or other undesirable consequences.

2. The reason why CSS does not inherit parent class styles

In actual development, we usually use CSS preprocessors, such as SASS or LESS, etc. These preprocessors Allows us to style elements using class or parent-child selectors. However, when using these selectors, we need to pay attention to the priority of the selector, because this may be one of the reasons why CSS does not inherit parent class styles.

In CSS, selectors have different priorities, which determine which style will be applied to an element. Typically, styles with higher priority will override styles with lower priority. The following is the priority order of CSS properties from high to low:

!important (highest priority)
Inline style
ID selector
Class, pseudo-class, attribute selector
Tag selector, pseudo-element selector
Wildcard selector
Inherited attributes

If the priority of a style is lower than the style in the parent class, then the child element will not inherit it. Also, if we define the same style in the parent and child elements, but their priorities are different, then the child element may inherit the styles in the parent element instead of the styles we define in the child element.

3. Solution

In order to avoid the problem that CSS does not inherit the parent class style, we can take the following measures:

a. Use inherited attributes

This is the easiest solution. We only need to use attributes in the parent element that can be inherited by the child elements, such as color, font-size, text-align, etc. This way, we can ensure that these styles will be inherited by child elements.

b. Use class selector

If we don’t want to use attributes that can be inherited, then we can use class selector to set the style of child elements. In this way, we can avoid selector priority issues while improving code maintainability.

c. Use child selectors or descendant selectors

You can also use child selectors or descendant selectors to style child elements. These selectors ensure that child elements only inherit the styles we want and not other styles. This approach also improves code maintainability.

Summary

In front-end development, style inheritance is a very useful feature, which allows us to write more concise and easy-to-maintain CSS code. However, it should be noted that the problem of CSS not inheriting the parent class style may occur. At this time, we need to understand concepts such as priority and selectors in order to better control the style.

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