CSS Introduction

CSS Introduction: CSS (Cascading Style Sheets) is a style sheet language used to add styling of elements in an HTML document or web page. It’s the tool that allows you to control the visual appearance of web pages, separate from the content itself.

  1. Selecting Elements: You use CSS selectors to target specific HTML elements you want to style. These selectors can target elements by their type, class, ID, attribute, or other criteria.
  2. Applying Styles: Once you’ve selected the elements, you define style rules using CSS properties and values. These properties control aspects like color, font, size, spacing, layout, borders, backgrounds, and more.
  3. Cascading: Multiple style sheets can be applied to a document, and the styles cascade, meaning they combine and inherit from one another according to specific rules. This allows for flexibility and organization in managing styles.
  • Inline: Directly within HTML elements using the style attribute (not recommended for maintainability).
  • Internal: Within the <head> section of an HTML document using a <style> tag.
  • External: In a separate CSS file linked to the HTML document using a <link> tag, which is the most common and preferred method for larger projects.
  • Separation of concerns: Keeps content (HTML) separate from presentation (CSS), making code overall more organized, maintainable, and reusable.
  • Enhanced visual appeal: Creates visually appealing and engaging web pages with various styling options.
  • Responsive design: Enables creating websites that adapt to different screen sizes and devices for optimal viewing experiences.
  • Improved accessibility: Proper CSS usage can enhance accessibility for users with disabilities by ensuring clear visual presentation and compatibility with assistive technologies.
  • Efficient updates: You can change the overall look and feel of a website by modifying a single CSS file, thus saving time and effort.
  • Reusability: CSS styles can be applied to multiple pages or elements at once, thereby reducing repetition and streamlining development.

CSS Styling Example:


/* This is a simple CSS rule that changes Heading 1 (h1) color and font size. */
h1 {
  color: blue;
  font-size: 2em;


  • Rules in CSS are written in a specific syntax (selector { property: value; }).
  • CSS selectors target HTML elements to apply styles.
  • Properties define the visual characteristics to change, while values specify the desired appearance for each property.
  • Lastly, experiment with different properties and values to create various styles and effects.