CSS Basic Coding | Learn CSS Basic

CSS (Cascading Style Sheets) is a stylesheet language used to describe the presentation of a document written in HTML. It allows you to control the layout, colors, fonts, and overall visual style of a web page. Here’s a basic introduction to CSS coding and some of the fundamental properties used to style HTML elements.

Basic Structure of a CSS File

CSS can be included in an HTML document in three ways: inline, internal, and external.

1. Inline CSS

Inline CSS is used to apply a unique style to a single HTML element. It uses the style attribute within the element’s tag.

<p style="color: blue; text-align: center;">This is a blue, centered paragraph.</p>

2. Internal CSS

Internal CSS is used to define styles for a single HTML document. The styles are defined within a <style> element in the <head> section.

<!DOCTYPE html> <html> <head> <style> body { background-color: lightgray; } h1 { color: blue; text-align: center; } p { font-family: Arial, sans-serif; font-size: 14px; } </style> </head> <body> <h1>This is a heading</h1> <p>This is a paragraph.</p> </body> </html>

3. External CSS

External CSS is used to define styles for multiple HTML pages. The styles are defined in an external .css file and linked to the HTML document using the <link> element.

style.css

body { background-color: lightgray; } h1 { color: blue; text-align: center; } p { font-family: Arial, sans-serif; font-size: 14px; }

index.html

<!DOCTYPE html> <html> <head> <link rel="stylesheet" type="text/css" href="style.css"> </head> <body> <h1>This is a heading</h1> <p>This is a paragraph.</p> </body> </html>

Basic CSS Syntax

A CSS rule consists of a selector and a declaration block:

selector { property: value; property: value; }
  • Selector: Specifies the HTML element you want to style.
  • Property: The aspect of the element you want to change (e.g., color, font-size).
  • Value: The value you want to apply to the property (e.g., blue, 14px).

Common CSS Selectors

  • Element Selector: Targets all instances of a given HTML element.
 p { color: red; }
  • ID Selector: Targets a single element with a specific id attribute. Prefixed with #.
 #header { background-color: yellow; }
  • Class Selector: Targets elements with a specific class attribute. Prefixed with ..
 .highlight { background-color: yellow; }
  • Universal Selector: Targets all elements.
 * { margin: 0; padding: 0; }
  • Attribute Selector: Targets elements with a specific attribute.
 [type="text"] { border: 1px solid black; }

Common CSS Properties

  • Color and Background
 color: blue; background-color: lightgray;
  • Font
 font-family: Arial, sans-serif; font-size: 16px; font-weight: bold;
  • Text
 text-align: center; text-decoration: underline;
  • Box Model (Spacing)
 margin: 20px; padding: 10px; border: 1px solid black;
  • Dimensions
 width: 100px; height: 200px;
  • Display and Positioning
 display: block; position: absolute; top: 50px; left: 100px;

Example of Applying CSS

Here is a simple example to demonstrate the application of various CSS properties:

style.css

body { background-color: lightgray; font-family: Arial, sans-serif; } h1 { color: blue; text-align: center; margin-top: 50px; } p { font-size: 14px; color: black; line-height: 1.6; margin: 20px; } #main-content { background-color: white; padding: 20px; border: 1px solid #ccc; width: 80%; margin: auto; } .highlight { background-color: yellow; font-weight: bold; }

index.html

<!DOCTYPE html> <html> <head> <link rel="stylesheet" type="text/css" href="style.css"> </head> <body> <h1>Welcome to My Webpage</h1> <div id="main-content"> <p>This is a paragraph inside the main content area. Here is some <span class="highlight">highlighted text</span>.</p> <p>Another paragraph with some more content.</p> </div> </body> </html>

By using CSS, you can significantly enhance the appearance and usability of your web pages.