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CSS specificity: A guide to managing style conflicts

IT, Programming, & Web Development › Forums › Web Development › HarvardX: CS50W – CS50’s Web Programming with Python and JavaScript › CS50W – Lecture 0 – HTML and CSS › CSS specificity: A guide to managing style conflicts

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  • July 9, 2024 at 5:56 am #2981
    Splendid Digital Solutions
    Keymaster

      Display of submit button controlled from which class
      byu/DigitalSplendid inweb_design

      Comment
      byu/DigitalSplendid from discussion
      inweb_design

      Source: Generated taking help of ChatGPT

      Sure, let’s dive deeper into CSS specificity and how it affects the order in which styles are applied to HTML elements.

      Understanding CSS Specificity

      CSS specificity is a set of rules applied by browsers to determine which style rule is applied to an element when multiple rules could apply. Specificity is calculated based on the types of selectors used in a rule.

      Categories of Selectors and Their Specificity Weights

      1. Inline Styles: Inline styles added directly to an element (style="...") have the highest specificity.
        • Example: <h1 style="color: pink;">
        • Specificity: 1000
      2. IDs: Selectors that target an element by its ID.
        • Example: #navbar
        • Specificity: 100
      3. Classes, Pseudo-classes, Attribute Selectors: Selectors that target an element by its class, pseudo-class, or attribute.
        • Examples: .test, :hover, [href]
        • Specificity: 10
      4. Elements and Pseudo-elements: Selectors that target an element by its type or pseudo-element.
        • Examples: h1, ::before
        • Specificity: 1

      Calculating Specificity

      To calculate specificity, we count the number of each type of selector in a compound selector and assign weights according to the above categories. The specificity is expressed as a combination of four values (a, b, c, d):

      • a: Inline styles (not applicable in most stylesheets)
      • b: ID selectors
      • c: Class selectors, attribute selectors, and pseudo-classes
      • d: Type selectors and pseudo-elements

      Each of these values is multiplied by its respective weight and then summed to get a final specificity score.

      Examples of Specificity Calculation

      Example 1: .google-submit

      • .google-submit is a class selector.
      • Specificity: 0 0 1 0 (10)

      Example 2: .buttons input[type="submit"]

      • .buttons is a class selector (c = 1).
      • input[type="submit"] is an element selector combined with an attribute selector (d = 1, c = 1).
      • Specificity: 0 0 2 1 (20 + 1 = 21)

      Why .buttons input[type="submit"] Has Higher Specificity

      The selector .buttons input[type="submit"] has a higher specificity score (21) compared to .google-submit (10). Therefore, when both selectors are applied to the same element, the styles defined in .buttons input[type="submit"] will take precedence over those defined in .google-submit.

      Practical Example

      <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Google Search</title>
    <link rel="stylesheet" href="styles/styles.css">
</head>
<body>
    <div class="buttons">
        <input type="submit" class="google-submit" value="Google Search" />
    </div>
</body>
</html>

      .google-submit {
    background-color: #f2f2f2; /* creamish color */
    color: #5f6368; /* grey text */
    border: 1px solid #dfe1e5; /* light grey border */
    border-radius: 4px; /* rounded corners */
    font-size: 14px;
    padding: 10px 20px;
    cursor: pointer;
    margin: 5px;
    transition: background-color 0.3s;
}

.buttons input[type="submit"] {
    background-color: #1a73e8; /* blue color */
    color: #fff; /* white text */
    border: none;
    border-radius: 4px;
    padding: 10px 20px;
    cursor: pointer;
}

      Explanation

      • The input element has both the google-submit class and is within a div with the class buttons.
      • .google-submit applies specific styles to the button.
      • .buttons input[type="submit"] targets the same button with higher specificity, overriding the background-color and color.

      Conclusion

      Understanding CSS specificity is crucial for effectively managing and troubleshooting style conflicts in web projects. By following the rules and calculating specificity correctly, you can predict which styles will be applied and ensure your design behaves as expected.

      Further Reading

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