CSS (Cascading Style Sheets) is a style sheet language used to describe the presentation of HTML elements. It is a core web technology, alongside HTML and JavaScript, that controls layout, colors, fonts, and overall visual appearance of web applications.
Key Features
Selectors and Pseudo-Classes
CSS provides powerful selectors and pseudo-classes (e.g., :nth-child, :hover, :not()) for precise element targeting.
Box Model
Defines how elements are sized and spaced, including content, padding, border, and margin.
Positioning and Layout
Supports positioning techniques (static, relative, absolute, fixed, sticky) as well as layout models like Flexbox and Grid for modern responsive design.
Typography and Colors
Controls fonts, text alignment, spacing, and colors using keywords, hex, RGB, HSL, and gradients.
Transitions and Animations
- Smooth state changes with
transitionproperties - Keyframe-based animations with
@keyframes
Responsive Design
Media queries enable adaptive styles based on device width, height, or other characteristics.
Custom Properties (CSS Variables)
Reusable variables defined with the --variable-name syntax allow consistency and easier theming.
Advantages
- Provides precise control over the look and feel of web pages
- Enables responsive and adaptive design for multiple devices
- Separation of structure (HTML) and style (CSS) improves maintainability
Purpose
CSS is fundamental for creating modern, responsive, and visually appealing websites, giving developers the tools to define layout, styling, and animations in a scalable way.