A complete CSS tutorial typically covers all aspects of CSS (Cascading Style Sheets), which is used to style and layout web pages. Here’s an outline of what a complete tutorial might look like, from basic to advanced topics.

1. Introduction to CSS

• What is CSS?
  • CSS stands for Cascading Style Sheets.
  • It controls the layout and design of HTML elements.
• How CSS Works
  • CSS rules consist of a selector and a declaration block.
  • Example:

h1 {
  color: blue;
  font-size: 20px;
}

2. CSS Syntax

• Selectors: Target HTML elements for styling.
  • Types: Universal (*), Class (.class), ID (#id), Element (div, p), Attribute, and Pseudo-selectors.
• Properties and Values: The style to apply, such as color, font-size, etc.
• Comments: /* This is a comment */

3. Adding CSS to HTML

• Inline CSS: Inside HTML tags via the style attribute.
  • Example: <h1 style="color: red;">Hello</h1>
• Internal CSS: Inside a <style> tag in the head section of an HTML document.
• External CSS: Linking to an external stylesheet with the <link> tag.
  • Example: <link rel="stylesheet" href="styles.css">

4. CSS Selectors

• Basic Selectors
  • Element (h1), Class (.class), ID (#id), Grouping (h1, p).
• Combinators
  • Descendant (div p), Child (div > p), Sibling (div + p, div ~ p).
• Pseudo-classes
  • :hover, :focus, :nth-child(), :nth-of-type().
• Pseudo-elements
  • ::before, ::after, ::first-letter, ::first-line.

5. CSS Box Model

• Content: The content of the box, where text and images appear.
• Padding: Space between the content and the border.
• Border: A border that surrounds the padding.
• Margin: Space outside the border, separating this box from other elements.
• Example:

div {
  padding: 10px;
  border: 1px solid black;
  margin: 20px;
}

6. CSS Colors

• Color Values:
  • Named colors: red, blue, green.
  • Hexadecimal: #ff0000.
  • RGB: rgb(255, 0, 0).
  • HSL: hsl(0, 100%, 50%).
• Opacity and Alpha Channel: Using rgba() or hsla() for transparency.

7. CSS Backgrounds

• Background-color: Set the background color of an element.
• Background-image: Set a background image for an element.
• Background-repeat: Repeat the background image vertically or horizontally.
• Background-size: Control the size of the background image.

body {
  background-color: lightblue;
  background-image: url('bg-image.jpg');
  background-size: cover;
}

8. CSS Fonts and Text

• Font-family: Set the font style.
• Font-size: Set the size of the text.
• Font-weight: Control the thickness of the text (bold, normal).
• Text-alignment: Align text (left, center, right).
• Text-decoration: Add underlines or strikethrough to text.
• Line-height: Adjust the spacing between lines of text.
• Letter-spacing and Word-spacing: Control the spacing between characters and words.

9. CSS Layouts

• Display Property
  • block, inline, inline-block, none.
• Position Property
  • static, relative, absolute, fixed, sticky.
  • Example of position: absolute:

div {
  position: absolute;
  top: 50px;
  left: 100px;
}

• Flexbox: A modern way to layout elements.
  • Flex container and flex items.
  • Properties like justify-content, align-items, flex-wrap.
  • Example:

.container {
  display: flex;
  justify-content: center;
  align-items: center;
}

• CSS Grid: Create complex layouts easily.
  • Grid container and grid items.
  • Properties like grid-template-columns, grid-template-rows, grid-gap.
  • Example:

.grid-container {
  display: grid;
  grid-template-columns: 1fr 2fr;
  grid-gap: 10px;
}

10. CSS Responsive Design

• Media Queries: Make the design responsive to different screen sizes.
  • Example:

@media (max-width: 600px) {
  body {
    background-color: lightgreen;
  }
}

• Responsive Units: Use %, em, rem, vw, and vh for responsive sizing.
• Responsive Images: Use max-width: 100% to make images scalable.
• Viewport Meta Tag: Optimize for mobile.
• Example:

11. CSS Animations and Transitions

• CSS Transitions: Smoothly transition between styles.
  • Example:

div {
  transition: background-color 2s;
}
div:hover {
  background-color: blue;
}

• CSS Animations: Create more complex animations using @keyframes.
  • Example

@keyframes example {
  from {background-color: red;}
  to {background-color: yellow;}
}
div {
  animation-name: example;
  animation-duration: 4s;
}

12. CSS Variables

• Declaring Variables: Use --variable-name to define CSS variables.
• Using Variables: Use var(--variable-name) to access variables.
• Example:

:root {
  --main-color: #3498db;
}
body {
  background-color: var(--main-color);
}

13. CSS Frameworks

• Popular CSS Frameworks: Bootstrap, Tailwind CSS, Bulma.
• Using Frameworks: Add pre-built classes for quick styling.

14. CSS Best Practices

• Keep CSS DRY (Don’t Repeat Yourself): Use classes and inheritance effectively.
• Use CSS Reset or Normalize: Eliminate browser inconsistencies.
• Organize Your CSS: Use comments, and organize rules by sections or components.
• Minify CSS for Production: Reduce file size and improve performance.

15. Advanced CSS Features

• CSS Grid: Advanced layouts using grid-area, grid-auto-flow.
• Advanced Selectors: Attribute selectors, complex pseudo-classes.
• CSS Functions: calc(), clamp(), min(), max().
• CSS Preprocessors: LESS, SASS.