CSS : selector priority / style inherit

selector priority

In CSS, selector priority determines which styles will be applied to an element when multiple conflicting styles are defined. CSS selectors have different levels of specificity, and the more specific a selector is, the higher its priority. Understanding selector priority is important to ensure that the intended styles are applied correctly.

The following factors contribute to selector priority, listed in ascending order of importance:

1. Selector Types: Different types of selectors have varying levels of specificity. Here are some common selector types, listed from lowest to highest specificity:
   • Type selectors (e.g., div, p, span)
   • Class selectors (e.g., .my-class)
   • ID selectors (e.g., #my-id)
   • Inline styles (applied directly to the HTML element using the style attribute)
   Inline styles have the highest specificity, while type selectors have the lowest.
2. Number of Selectors: When multiple selectors target the same element, the selector with more components or levels generally has higher specificity. For example, the selector body .container is more specific than just .container.
3. ID Selectors vs. Class Selectors: ID selectors have a higher specificity than class selectors. If conflicting styles are applied using these selectors, the styles defined by the ID selector will take precedence over the class selector.
4. !important Rule: When a style rule includes the !important declaration, it has the highest priority and overrides any other conflicting styles. However, it is generally recommended to use !important sparingly, as it can make the code harder to maintain and override.
5. Specificity Calculation: Specificity can be calculated by assigning a weight to each component of a selector and summing them up. The calculation is as follows:
   • ID selectors contribute 100 points to the specificity.
   • Class selectors contribute 10 points to the specificity.
   • Type selectors contribute 1 point to the specificity.
   For example, the selector body .container#my-element would have a specificity of 112 (1 for the type selector, 10 for the class selector, and 100 for the ID selector).

In general, it's best to use selectors that are as specific as necessary to target the desired elements without unnecessarily increasing specificity. This helps maintain code readability and ease of maintenance.

 

style inherit

In CSS, the inherit keyword is used to explicitly specify that a property value should be inherited from the parent element. It allows you to apply the same style as the parent element to a child element.

 

By default, most CSS properties are inherited by child elements. This means that if you don't specify a value for a property in a child element, it will inherit the computed value from its parent element. However, some properties, such as border, margin, and padding, are not inherited.

 

Using the inherit keyword overrides the default inheritance behavior and explicitly instructs the child element to adopt the value of the specified property from its parent element.

 

Here's an example to illustrate how inherit works:

<style>
  .parent {
    color: red;
    font-size: 16px;
  }
  .child {
    color: inherit;
    font-size: inherit;
  }
</style>

<div class="parent">
  Parent element with red text and font size 16px.
  <div class="child">
    Child element with inherited styles from parent.
  </div>
</div>

In this example, the .parent class sets the color to red and the font size to 16 pixels. The .child class uses the inherit keyword for the color and font-size properties. As a result, the child element inherits the red color and font size of the parent element.

 

It's important to note that inherit only works when there is a parent element with a defined value for the property you want to inherit. If there is no explicit value set on the parent element, inherit will have no effect.

Additionally, some properties, like display and position, cannot be inherited. In these cases, using inherit will have no impact, and you need to manually specify the desired value for the child element.

 

Overall, the inherit keyword provides a way to explicitly ensure that specific properties are inherited from the parent element, allowing for more control over cascading styles in CSS.