Difference Between CSS and CSS3: A Complete Guide

CSS (Cascading Style Sheets) is the backbone of modern web design, allowing developers to style and format HTML elements. Over the years, CSS has evolved, with CSS3 introducing significant improvements and new features.

In this blog, we’ll explore the key differences between CSS and CSS3, covering new features, improvements, and practical use cases.

1. What is CSS?

CSS (Cascading Style Sheets) is a stylesheet language used to control the presentation of HTML documents. It allows developers to:

✔ Style text (fonts, colors, spacing)
✔ Control layout and positioning
✔ Improve responsiveness for different screen sizes

However, earlier versions of CSS had limitations, requiring developers to rely on JavaScript and images for advanced designs.

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2. What is CSS3?

CSS3 is the latest evolution of CSS, introducing new modules and features to enhance web design. Instead of being a single specification like CSS, CSS3 is divided into modules, each handling specific functionalities.

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3. Key Differences Between CSS and CSS3

Feature	CSS	CSS3
Architecture	Single specification	Divided into multiple modules
Animations	Not supported	Supports @keyframes animations
Gradients	Background images required	Supports linear and radial gradients
Rounded Corners	Required images or JavaScript	Supports border-radius
Box Shadows	Not available	Introduced with box-shadow
Flexbox & Grid	Not available	Supports modern layout techniques
Media Queries	Not available	Supports responsive design
Opacity	Used filters and hacks	Supports opacity property
Custom Fonts	Limited to system fonts	Supports @font-face and Google Fonts

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4. Key Features Introduced in CSS3

A. Responsive Design with Media Queries

CSS3 introduced media queries, allowing styles to change based on screen size.

@media (max-width: 768px) {
    body {
        background-color: lightgray;
    }
}

✔ This makes websites mobile-friendly without extra JavaScript.

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B. Animations & Transitions

CSS3 supports animations and smooth transitions, reducing the need for JavaScript.

button {
    transition: background-color 0.5s ease-in-out;
}

button:hover {
    background-color: blue;
}

✔ Creates a smooth hover effect without JavaScript.

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C. Rounded Corners with border-radius

Before CSS3, developers used images to create rounded corners. Now, it’s simpler:

.box {
    width: 100px;
    height: 100px;
    background-color: red;
    border-radius: 10px;
}

✔ Adds rounded corners effortlessly.

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D. Text Effects & Custom Fonts

CSS3 allows custom fonts with @font-face:

@font-face {
    font-family: 'CustomFont';
    src: url('customfont.ttf');
}

h1 {
    font-family: 'CustomFont', sans-serif;
}

✔ Enables unique typography without images.

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E. Box Shadow & Text Shadow

Adds depth and contrast to UI elements.

.box {
    box-shadow: 5px 5px 10px gray;
}

h1 {
    text-shadow: 2px 2px 4px gray;
}

✔ Creates a modern UI design.

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F. Flexbox & Grid for Advanced Layouts

CSS3 introduced Flexbox and Grid for easy, responsive layouts.

Flexbox Example:

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

✔ Aligns items easily and responsively.

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5. Conclusion: Should You Use CSS3?

Yes! CSS3 is faster, more powerful, and mobile-friendly. It eliminates the need for extra JavaScript and images, making websites more efficient.

Why Use CSS3?

✔ Supports modern animations and effects
✔ Enables responsive design
✔ Reduces reliance on JavaScript
✔ Improves website performance