What is External CSS?
External CSS is a method of applying
styles to a webpage by linking an external CSS file to the HTML document. The
CSS rules are written in a separate file with a .css extension and then linked to the
HTML using the <link> tag in the <head> section.
This approach allows you to reuse
the same stylesheet across multiple webpages, making it efficient for managing
large projects.
Key Features of External CSS:
- Separation of Concerns
- The HTML structure and CSS styling are kept in
separate files, making the code easier to read, manage, and maintain.
- Reusability
- A single CSS file can be linked to multiple HTML
documents, ensuring consistent styling across an entire website.
- Scalability
- External CSS is ideal for large projects with numerous
pages, as updates to the CSS file automatically reflect across all linked
pages.
Example of External CSS
Step 1: Create a CSS File (style.css)
/*
Styling for the body */
body {
font-family: Arial, sans-serif;
background-color: #f8f9fa; /* Light gray background */
margin: 20px;
color: #333; /* Dark gray text */
}
/* Styling for the main heading */
h1 {
color: darkblue;
text-align: center;
font-size: 2.5em;
margin-bottom: 20px;
}
/* Styling for a paragraph */
p {
font-size: 1.2em;
line-height: 1.6;
margin-bottom: 15px;
}
Step 2: Link the CSS File to an HTML Document (index.html)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>External CSS Example</title>
<!-- Linking the external CSS file -->
<link rel="stylesheet" href="style.css">
</head>
<body>
<h1>Welcome to External CSS</h1>
<p>
This webpage is styled using an external CSS file. External CSS ensures consistency and makes it easier to maintain styles across multiple pages.</p></body></html>
When to Use External CSS:
- For websites with multiple pages that need consistent
styling.
- When maintaining a clean and structured codebase is
essential.
- For projects requiring a scalable approach to styling.
Advantages of External CSS:
- Consistency:
Styles can be applied uniformly across all pages.
- Efficiency:
Changes made in the CSS file update all linked pages instantly.
- Clean Code:
HTML files remain uncluttered, focusing solely on content and structure.
Limitations of External CSS:
- Dependency:
If the CSS file is unavailable (e.g., due to a broken link), the webpage
will display without styling.
- Additional Request:
The browser must make an additional HTTP request to fetch the CSS file,
which could slightly impact load times.
External CSS is the most commonly
used method in professional web development, as it offers flexibility, maintainability,
and scalability for projects of any size.