Basics of CSS

 

Introduction to CSS: Styling the Web

CSS (Cascading Style Sheets) is a styling language used to describe the look and formatting of HTML documents. With CSS, we can control the layout, colors, fonts, spacing, and more, making our websites attractive and user-friendly.

Key Concepts in CSS

  1. Selectors: CSS selectors target HTML elements to apply specific styles.
  2. Properties and Values: Each CSS rule consists of a property (like color or font-size) and a value.
  3. CSS Syntax: Basic CSS syntax involves a selector, followed by curly braces {}, containing property-value pairs.

CSS Syntax

A CSS rule has the following syntax:

selector {

    property: value;

}

For example:
h1 {
    color: blue;
    font-size: 24px;
}

Ways to Add CSS

  1. Inline CSS: Add CSS directly to an HTML element using the style attribute.
  2. Internal CSS: Use the <style> tag within the HTML <head>.
  3. External CSS: Link a CSS file using <link rel="stylesheet" href="style.css"> in the HTML <head>.

Basic Elements of CSS

1. Selectors

CSS selectors allow us to target HTML elements.

  • Element Selector: Targets all elements of a specific type.

p {
    color: green;
}

Class Selector: Targets elements with a specific class attribute (use .className).

.highlight {
    background-color: yellow;
}

ID Selector: Targets a single element with a specific ID attribute (use #idName).

#main-heading {
    font-size: 30px;
}

2. Properties and Values

Each CSS property affects a different aspect of the element's appearance.

  • Color: Sets the color of the text.

h1 {
    color: red;
}

  • Font: Controls the font style, size, and weight.
p {
    font-family: Arial, sans-serif;
    font-size: 16px;
}

  • Background: Sets the background color or image of an element.
body {
    background-color: #f0f0f0;
}

3. CSS Box Model

Every HTML element is a rectangular box and has margins, borders, padding, and content.

  • Margin: Creates space around an element.

.container {
    margin: 20px;
}
  • Padding: Creates space inside the element, around the content.
.container {
    padding: 15px;
}
  • Border: Adds a border around the element.
.container {
    border: 1px solid black;
}

4. Text Styling

CSS provides many ways to style text.

  • Text Alignment:

h1 {
    text-align: center;
}

  • Text Decoration:
a {
    text-decoration: none;
}

Example: Applying CSS to an HTML Page

Here’s a simple example to demonstrate CSS basics.

HTML:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS Basics</title>
    <link rel="stylesheet" href="styles.css">
</head>
<body>
    <h1 id="main-heading">Welcome to CSS Basics</h1>
    <p class="intro">CSS makes the web beautiful and easy to use.</p>
    <p class="highlight">Learn CSS and enhance your web development skills!</p>
</body>
</html>

CSS (styles.css):
/* Applying styles to the body */
body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 0;
    padding: 0;
}

/* Styling the main heading */
#main-heading {
    color: darkblue;
    font-size: 36px;
    text-align: center;
    margin-top: 20px;
}

/* Styling paragraphs */
p {
    color: #333;
    font-size: 18px;
    margin: 10px 20px;
}

/* Highlighted text */
.highlight {
    background-color: yellow;
    font-weight: bold;
}

In this example:

  • We’ve styled the body, heading, and paragraphs.
  • We used an ID selector for the #main-heading.
  • The .intro and .highlight class selectors apply different styles to paragraphs.

Running Your CSS Code

To see the CSS in action:

  1. Save the HTML code in a file named index.html.
  2. Save the CSS code in a file named styles.css.
  3. Open index.html in a web browser, and observe the styles applied.

Conclusion

CSS is essential in web design, allowing for customization and enhancing user experience. Understanding CSS basics is the first step toward creating attractive, functional websites. Keep experimenting with different styles to see how they impact your webpage’s appearance.

Inline CSS

Inline CSS allows you to apply styles directly to an HTML element using the style attribute, which is placed inside the opening tag of the element. Here are some examples that illustrate how to use inline CSS.

Inline CSS Examples

1. Changing Text Color

To change the color of a heading directly, you can use inline CSS like this:

<h1 style="color: blue;">This is a Blue Heading</h1>

This example applies the color blue only to this specific <h1> element.

2. Setting Background Color

To set a background color for a paragraph:

<p style="background-color: lightgrey;">This paragraph has a light grey background.</p>

The background-color property only affects this paragraph, leaving other paragraphs unaffected.

3. Adjusting Font Size and Style

To customize the font size and style:

<p style="font-size: 20px; font-family: Arial, sans-serif;">This paragraph has custom font size and style.</p>

Here, the font size is set to 20 pixels, and the font family is set to Arial.

4. Adding Border and Padding

To add a border and padding around a div:

<div style="border: 2px solid black; padding: 10px;">

    This div has a black border and padding inside.

</div>

This div element has a solid black border and padding that creates space inside the border.

5. Centering Text with Inline CSS

To center-align text in an element:

<h2 style="text-align: center;">This text is centered.</h2>

The text-align: center; rule centers the text within the element.

6. Setting Width and Margin for Alignment

You can control the width and alignment of elements using width and margin.

<div style="width: 50%; margin: 0 auto; background-color: #f0f0f0; text-align: center;">

    This div is centered and has a 50% width.

</div>

Here:

  • width: 50%; makes the div half as wide as its container.
  • margin: 0 auto; centers it horizontally within the container.

7. Changing Link Styles

You can style a specific link using inline CSS:

<a href="https://example.com" style="color: green; text-decoration: none;">Visit Example</a>

This changes the link color to green and removes the underline.

Combining Multiple Inline Styles

You can apply multiple styles at once by separating each property-value pair with a semicolon:

<p style="color: white; background-color: darkblue; padding: 10px; font-weight: bold;">

    This paragraph has multiple inline styles.

</p>

This paragraph has white text on a dark blue background, with padding and bold text.

Inline CSS is useful for quick, single-use styling, but remember that using too much inline CSS can make the code harder to maintain. For larger projects, consider using internal or external CSS for a more organized approach.

Internal CSS

Internal CSS is added within the <style> element inside the <head> section of the HTML document. This method allows you to apply styles to multiple elements on the same page without needing an external CSS file. Here are some examples to demonstrate how internal CSS works.

Internal CSS Examples

To use internal CSS, place the CSS code inside a <style> tag in the HTML <head>, like this:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Internal CSS Example</title>
    <style>
        /* Changing text color and alignment for headings */
        h1 {
            color: darkblue;
            text-align: center;
        }

        /* Styling paragraphs with font size and color */
        p {
            font-size: 18px;
            color: #555;
        }

        /* Styling divs with background color, padding, and border */
        .container {
            background-color: #f4f4f4;
            padding: 20px;
            border: 1px solid #ddd;
            margin: 10px 0;
        }

        /* Setting specific styles for links */
        a {
            color: green;
            text-decoration: none;
        }

        /* Adding a hover effect to links */
        a:hover {
            color: darkgreen;
            text-decoration: underline;
        }
    </style>
</head>
<body>
    <h1>Welcome to Internal CSS</h1>
    <p>This is a paragraph styled with internal CSS. Internal CSS applies styles to multiple elements on a single page.</p>

    <div class="container">
        <p>This div has a light grey background, padding, and a border.</p>
    </div>

    <a href="#">This is a link styled with internal CSS.</a>
</body>
</html>

Explanation of Each Section

  1. Headings:

    • h1 elements are styled to have a dark blue color and centered alignment.

  2. Paragraphs:

    • p elements have a font size of 18 pixels and a light grey text color (#555).

  3. Containers:

    • The .container class adds styles to any <div class="container"> element, giving it a light grey background, padding, a border, and some vertical spacing.

  4. Links:

    • a elements (links) are given a green color with no underline.
    • When the user hovers over a link, the color changes to dark green, and an underline appears.

Benefits of Internal CSS

Internal CSS is useful for:

  • Small projects or single-page sites where styles don’t need to be reused across multiple pages.
  • Quick customization of a single page without needing an external stylesheet.

By using internal CSS, you can keep your styles organized within the same HTML file, making it easy to manage while learning CSS or working on small projects.

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