Google News
CSS3 Interview Questions
The first working draft of CSS3 came in 19-01-2001. but it was initially declared early in the June 1999. The main difference between css2 and css3 is Media Queries, Namespaces, Selectors Level 3, Color.
CSS3 has been split into "modules". It contains the "old CSS specification". In addition, new modules are added.

Ex :  Selectors, Box Model, Backgrounds, Borders, Gradients, shadows, Image Values and Replaced Content, Text Effects, 2D Transformations, 3D Transformations, Transitions, Animations,  Multiple Column Layout, User Interface, etc,..
3 following border futures added :
• border-radius
• box-shadow
• border-image
To Allow long words to be able to break and wrap onto the next line in css3 we used word-wrap property like below class
When the animation is created in the @keyframe, bind it to a selector, otherwise the animation will have no effect.
Bind the animation to a selector by specifying at least these two CSS3 animation properties :
• Specify the name of the animation
• Specify the duration of the animation
Opacity is a style property used to show or hide the html element.
For example 0 for hide and 1 for show.

<p style="opacity: 0">Show Me</p>
<p style="opacity: 0.5">Show Me</p>
<p style="opacity: 1">Show Me</p>

The Opacity declaration sets how opaque an element is.An opacity value of 1 means the element is fully opaque. An opacity value of 0 means an element is not at all opaque, i.e. fully transparent.This elements opacity is 0.5 .
Note : That both the text and the background-color are affected by the opacity level.
If you want to use the multiple background ,we can insert as follows...

background-image : url(image.png), url(image-2.png), url(image-3.jpg); also we can mention the position of the image either percentage value or top left, left center like this.
Media queries are introduced in CSS3, which are directly used for making website responsive i.e. RWD (Responsive Web Designing). Get more guidance on Responsive Web Design Tutorials with step by step guidance!
Flexbox is the new layout modal being used in CSS3. Used along with display, its primary function is to control the elements behaviour in multiple screen sizes and devices.
CSS3 multiple Column property is easiest way of dividing section of particular element just like in newspaper and there are various rule applied to it regarding count, gap, rule, style, width, color and span.