Yes their is so many difference between CSS2 & CSS3. CSS3 is the latest standard version for CSS & currently under development. but CSS2 was developed by the W3C and published as a Recommendation in May 1998. The biggest difference between CSS2 and CSS3 is that CSS2 was a single document with all the Cascading Style Sheets, but CSS3 have different sections of each style, called modules. Each module is making it’s way through the W3C in various stages of the recommendation process.each module is being worked on individually,so their is much wider range of browser support for CSS3 modules. CSS3 is the latest standard version for CSS & currently under development. but CSS2 was developed by the W3C and published as a Recommendation in May 1998.
Many exciting new functions and features are being lined up for CSS3 but CSS2 haven’t these functions and features.
1) Text Changes in CSS3
CSS3 have more text-effect feature that text is handled in an HTML document in an attempt to better replicate the layout controls available to newspaper or magazine editors. New CSS3 specifications. Designers can also set the width of the tab space and the way that HTML by default condenses multiple spaces into a single one.Border Changes in CSS3 but in CSS2 it’s not possible.
2) Border changes
CSS3 have several new tools in laying out borders. In CSS3, borders can be rounded rather than straight; they can also be composed of images. In CSS3 we can change background image with tiles images or gradient color or video clip in fixed or flexible width or height . but in CSS2 it’s not possible.
3)Columns in CSS3
IF you have text-heavy page , then you can use most powerful new tools in CSS3 that is columns property, which to you to divide length of text into any number of columns with variable width and size.As in a newspaper, you can see each column is effectively its own with & height , so images placed within the column re-size to the width of that column rather than the entire text block or website. but in CSS2 we can’t use Column property.only one column can define text. or web page.
4) Color Code
In CSS3 we can use gradient color for text background or images border, we can use
HSLA colors(Hue Saturation Lightness (and alpha)) , opacity ( The CSS3 property for transparency is opacity), RGBA colors ( red green blue alpha ) color code for our design to make represent imapctful & logically; but in CSS2 we have no option of these features;
In CSS3, some of the new user interface features are resizing elements, box sizing, and outlining. in resizing elements a div element should be re-sizable by the user,
In box-sizing property allows you to define certain elements to fit an area in a own way
for example :-
-moz-box-sizing:border-box; /* Firefox */
and by Outlining we can fit a outline outside the border edge :-
border:2px solid black;
outline:2px solid red;
In above their will a outline in 15px outside the border edge;