CSS

CSS stands for Cascading Style Sheets.

It is a language used to style and design web pages—specifically, to control how HTML elements look and appear in the browser.

What CSS does

CSS handles the visual presentation of a website, including:

• Colors
• Fonts and text sizes
• Spacing and layout
• Backgrounds and borders
• Animations and transitions
• Responsive design for different screen sizes (mobile, tablet, desktop)

How CSS works

HTML provides the structure of a page, while CSS provides the style.

Example:

<p>Hello World</p>

With CSS:

p {
  color: blue;
  font-size: 18px;
}

This CSS makes the paragraph text blue and larger.

Why it’s called “Cascading”

The term cascading means CSS follows a priority system:

• Browser default styles
• External stylesheets
• Internal styles
• Inline styles (highest priority)

If multiple rules apply to the same element, CSS decides which one wins based on specificity and order.

Where CSS can be used

• Inline CSS – inside an HTML element
• Internal CSS – inside a <style> tag
• External CSS – in a separate .css file (best practice)

Why CSS is important

• Separates content from design
• Makes websites easier to maintain
• Enables responsive and modern layouts
• Improves performance and consistency

In short:
HTML builds the page, CSS makes it look good.