CSS3 (Cascading Style Sheets version 3) is the latest version of the language used for describing the presentation of web pages. It is used to style and layout HTML documents, separating the presentation of a document from its structure.

CSS3 includes many new features and capabilities, such as:

• Selectors: Allows for more advanced selection of elements on a page, such as selecting elements based on their attributes or their position within the document.
• Box-sizing: Allows for more control over the size of elements, including the ability to include padding and border in the total size of an element.
• Border and Backgrounds: Allows for more control over the appearance of borders and backgrounds, including the ability to create rounded corners and multiple background images.
• Text Effects: Allows for more advanced typography, such as text shadows, word wrapping, and hyphenation.
• 2D/3D Transformations: Allows for the manipulation of elements in two- or three-dimensional space, including the ability to rotate, skew, and scale elements.
• Animation and Transitions: Allows for the creation of smooth and fluid animations and transitions between different states of an element.
• Media Queries: Allows for the creation of responsive designs that adapt to different screen sizes and resolutions.
• Flexbox and Grid: Allows for more advanced layout capabilities, including the ability to create flexible and responsive grid-based layouts.