CSS3 Interview Questions and Answers

Web page designing is a creative task, and if the right technology is used, it becomes effortless work for developers. Developers need to keep updating their technical skill set. They can easily learn the most demanding technology, CSS3, which supports all the latest browsers. It's a level 3 version of CSS. The full form of CSS is Cascading Style Sheets.

Before going to study the latest questions and answers, let's know some facts about CSS3:

• The first vision was launched on 17th December 1996. The latest version is CSS 3.1 Level 3 Revision 1 released on 1999. 
• CSS 3 Developer’s average salary in India as a fresher is 25k/ month, and in the US as an experienced is $65k to $69k/ year.
• The “Father of CSS” is Mr. Hakon Wium Lie.

We are sure that our CSS3 interview questions can help you in cracking the interview and bagging your dream job with the highest payout.

We have categorized CSS3 Interview Questions - 2023 (Updated) into 3 stages:

• Freshers
• Experienced
• CSS3 FAQs

Frequently Asked CSS3 Interview Questions

1. What do you know about the CSS3 element selector?
2. What is the ruleset in CSS3?
3. What are the various font attributes available in CSS3?
4. Where can we use the class selector?
5. How we can restore property values in CSS3?
6. Explain Grouping in CSS3.
7. Explain the Float property of CSS3.
8. What is Image repetition backup?
9. Tell me how we can declare element dimension? 
10. What do you know about CSS3 Flexbox?

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CSS3 Interview Questions and Answers For Freshers

1. Tell me all three elements of CSS3?

CSS3 has the elements as syntax rules; they are

• Selector.
• Property.
• It's Value.

2. What do you know about the CSS3 element selector?

CSS3 element selector helps to find out the HTML elements name which we want to apply in a style sheet. It has five categories. They are

• Attribute Selectors: Find an attribute or attribute value of an HTML element.
• Combinator Selectors: Find a specific relationship between elements.
• Simple Selectors: Find a name, id, or class of an element.
• Pseudo Class Selectors: Find a certain state of an element.
• Pseudo Elements Selectors: Find the style part and select an element.

Example:

P {
text-align: left;
Color: blue

In the output element P will be left aligned with the Blue text color.

3. What are the media we can add in CSS3?

Mostly we customize the design by using media. We need media control to make the external style sheet. Through the network, we can also retrieve and load in CSS3. List of media:

• braille: Suitable for braille tactile feedback devices.
• embossed: Suitable for barrel printers.
• all: Can be used for all devices.
• handheld: Suitable for small screens with limited bandwidth.
• print: Suitable for show print preview before printing.
• screen: Suitable for a projector.
• tty: Can be used for teletypes or portable display devices.
• speech: It helps to identify the synthesizer.
• tv: Provides connection with television devices with color, sound, low resolution, and small scroll area.
• screen: it helps to color computer display screen like PC screen or Laptop screen.

4. Tell me the differences between Physical tags and Logical tags.

Physical tags can be used to mark up presentations or appearances. Logical tags can not be used for markup, presentation, or appearances. 

The latest tag version is a physical tag type. The logical tag type is an older version of the tag.

Physical tag is concentrated on all media. Logical tags concentrated on HTML content only.

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5. Do you think that a style sheet is different from HTML?

Yes, they are different. Because style sheets provide more styling, HTML provides less. If we use style sheets then we can get better formatting options and maximum browser compatibility.

6. What is the ruleset in CSS3?

One selector can be added to another selector by using the ruleset. It has two steps:

• Selector R 
• Declaration {text-indent: 12pt}.

7. Is CSS3 case sensitive?

CSS3 is not case sensitive, even also not dependent on font styles, or images on a website. But, if we do use XML then DOCTYPE will be XHTML, in that case, CSS3 will be case sensitive.

8. Explain the declaration block in CSS3.

The declaration block is actually a bundle of consisting property, colon, and value within braces. Like [property 2: value 5]

9. What are the various font attributes available in CSS3?

The various font attributes are

• Caption.
• Font Family.
• Font Style.
• Font Weight.
• Icon.
• Font size and height.
• Font variant.

10. Can we insert a file by importing it in CSS3?

Yes, we can insert the file. Actually importing activates the combining sheets to be attached to other sheets. Here we can use different files and sheets for a few functions. So we can use this given syntax:

@import notation, used with <Style> tag.

11. Where can we use the class selector?

This class selector is always unique to a particular style. It helps to manage the style declaration and association with HTML. Try this syntax:

classname
It can be A or any letter or digit.)
.botton {font: 16em;}, class selector
<Body class="bottom">

this class is tagged with element </body>

12. Explain the Pseudo element.

See in CSS3 Pseudo-elements are used by some selectors to add some special effects like styles in HTML normal markup level. But in some special cases, we can not add any document. In those cases, we can also use Pseudo-elements. Because it helps to mark up the document without distributing it.

13. Can we overrule underlining hyperlinks?

Yes, we can overrule underlining hyperlinks.

B {
Text-decoration:none:
}
<b href="career.html" style="text-decoration: none">link text </B>

14. Can we use 100 % of the width over the page?

Yes, we can use it. When we declare the float then 1 pixel will be added every time. It can be added more to the border of the form with more floats.

15. How we can restore property values in CSS3?

Sorry, we can revert the back value in CSS3. Because there are fewer default values. But we can re-declare the property to take out the default property.

16. Explain the CSS3 box model.

Actually, this box model contains the design and the element layout of CSS3. It has a few elements. Like:

• Margin: Overall structure shoes in this topmost layer within this margin.
• Border: Around the structure, the whole padding with contents is shown with color effects on the border.
• Padding: It shows the spaces in content within the border.
• Content: It shows the whole content.

17. What do we know about the contextual selector?

Contextual selectors are applied to special occurrences of a particular element. Here one space separates the different elements. The last element will be counted as a contextual selector like tdptextcolor {color: orange}.

18. Tell me the differences between Hexadecimal color codes and compare RGB values.

Hexadecimal color code uses a set of 6 characters and numbers. Whereas RGB uses 3 sets of 3 numbers with a range of 0-255. 

19. Explain Grouping in CSS3.

We can group the selector with the same values of property and the development code will be reduced. Now if they are having the same property then we can use commas to avoid rewriting.

Example:

h1 {
color: pink;
}
h2 {
color: pink;
}
p {
color: pink;
}

20. How to use Nesting CSS3?

Suppose, we want to specify a selector inside of a selector, then we have to use nesting in CSS3.

Example:

p
{
color: black;
text-align: right;
}
.marked
{
background-color: white;
}
.marked p
{
color: orange;
}

CSS3 Interview Questions For Experienced

21. Tell me the difference between the class selector and id-selector.

The overall block is called a class selector, but a single element that is different from others elements is called an id selector.

Example of class selector:

<style>
.center {
text-align: center;
color:red;
}
</style>

Example of id selector:

<style>
#para1
{
text-align: centre;
color:red;
}
</style>

22. What is the basic difference between visibility: hidden and display: none?

They are different in properties in the case of the former, the element is deleted, the element is hidden or no space is consumed.

23. Explain the Float property of CSS3.

We can wrap the text and position it on the left or right without changing the element's property. If we need to move the images on web pages then we have to use the float property. We can move the right of the image to the left or left to right along with the attached text.

24. What is the CSS3 counter?

Actually, this CSS3 counter is a variable. We can increase this variable value by using CSS3 inspect, even if we can find the number of times we have used the variable.

25. What is the utilization of background-position property?

When we want to declare the initial position of a particular background image, we have to do it through the background-position property. By default, the position is top left of the page. We can set the position as per our requirement, like right or corner or center, etc.

Example:

<html>
<head>
<style>
body {
background-image: url('mindmajix.gif');
background-repeat: no-repeat;
background-attachment: fixed;
background-position: center;
}
<p> CSS Background Position: Mindmajix.io</p>
</body>
</html>

26. What is Image repetition backup?

Actually, the background repetition property controls this backup process. If we are not repeating the image then we have to use no-repeat.

Example:

<html>
<head>
<style>
body {
background-image: url("/css/images/css.jpg");
background-repeat: no-repeat;

}
</style>
</head>
<body>
<p> CSS Background Position: Mindmajix.io</p>
</body>

27. Explain CSS3 Opacity.

Opacity means a certain degree that is applicable to light that passes through the objects in the pages. Actually, in CSS3 we control the transparency of any HTML elements by using opacity. It makes the images clear and visible. We can control opacity in two ways. 

First: We can declare it by @media or @import at-rules of specific target medium:

@import url("fancyfonts.css") screen;
@media print {
 /*style sheet for print goes here*/
}

Second: Within the HTML4 document, we can declare the media attribute.

<!DOCTYPE HTML PUBLIC"-//W3C//DTD HTML 4.01//EN">
</HTML?
 <HEAD>
  <TITLE>Link to a target medium</TITLE>
  <LINK REL="stylesheet" TYPE="text/css"
        MEDIA="print,handheld" HREF="foo.css">
  </HEAD>
 <BODY>
   <P>The body...
 </BODY>
</HTML>

28. Tell me how we can declare element dimension? 

We can define the element dimension by the given properties:

• Width.
• Min Width.
• Max Width.
• Height.
• Min Height.
• Max Height.

29. Explain Z-index in CSS3. 

If we are overlapping the elements vertically then we must use a z-index. It provides the vertical stack order of the elements. The default value we need to take is 0 in positive or negative. Also, we can the given values for z-index:

• Inherit.
• Initial.
• Auto.
• Number.

Let's see in the given below image:

30. What do you know about CSS3 Flexbox?

It's a flexible box in CSS, also available in CSS3. It provides proper orientation of elements in web pages, easy layout handling, and space distribution within elements in a responsive website. We can also handle the dimensions of elements by using the flexbox property. It has a few properties. They are

1. Flex wrap: Identify whether the items should be wrapped or not.
2. Flex Direction: Identify the direction of the container to be stacked.
3. Flex Flow: Identify the flow direction and wrapping in one action.
4. Justify Content: Control the content alignment.
5. Align Items: Used to align flex items.
6. Align Content: Used to align flex lines.

Most Common CSS3 FAQs

1. What do you know about CSS?

We can outline and fix the behavior of the HTML webpage by CSS. It helps to represent the HTML content on-screen by separating them from the presentation to take control of the website easier. Mostly the third version of CSS, that is CSS3 helps create the style and web page format. It has some advanced features from CSS2.

2. What modules are available in the latest CSS3?

The latest CSS3 modules are :

• Selectors [SELECT]
• Values and Units [CSS3VAL]
• Cascading & Inheritance [CSS3CASCADE].

It also has other informative modules:

• Media Queries [MEDIAQ]
• Generated Content [CSS3GENCON].

3. List the differences between CSS2 and CSS3

CSS2	CSS3
CSS2 comprises one module onl	CSS3 has many modules
CSS2 is difficult to handle	CSS3 is easier to handle
No specific fonts like Google fonts or Typecast are available in CSS2	In CSS3 special fonts like Google fonts and Typecast is available
Graphics-related features are not available in CSS2.	Graphics-related features are not available in CSS3.

4. Tell me about the different types of CSS.

Mainly, CSS is used to create the style in web pages that have HTML content. There are three types of CSS. They are

• Inline CSS.
• Internal or Embedded CSS.
• External CSS.

5. Why do we use an external style sheet?

External style CSS has different CSS files. These files have only the style property for the tag attributes like class, id, etc. It creates a separate file with a .css extension which we have like with HTML content by using a link tag. Only one time do we need to set the style which will be applied over web pages.

Example of external style sheet: mindmajix.css

body {
  background-color:powderblue;
}
.main {
  text-align:left;
}
.GFG {
  color:#009900;
  font-size:50px;
  font-weight:bold;
}
#mindmajix {
  font-style:bold;
  font-size:25px;
}

6. What is the use of internal style sheets?

This internal style sheet is used in HTML content uniquely. We have to keep it within the HTML file head section.

Example of internal style sheet:

<!DOCTYPE html>
<html>
  <head>
    <title>Internal CSS</title>
    <style>
      .main {
        text-align:center;
     }
     .GFG {
 	 color:#009900;
	 font-size:30px;
	 font-weight:bold;
     }
     .mindmajix {
	font-style:bold;
	font-size:10px;
     }
    </style>
   </head>
   <body>
     <div class="main">
       <div class="MDM">Mindmajix</div>
	
       <dic class="Mindmajix">
	 IT E-learning Portal.
       </div>
     </div>
   </body>
</html>

7. Explain CSS image scripts.

CSS image scripts can combine multiple images into a single image file, which we can use on web pages to increase performance better.

8. What do you mean by Responsive website?

Nowadays we use different electronic devices to access any website. So the screen size will be different as per the device. This responsive design helps the website to fit itself automatically accordingly to the screen size. It has flexible grids, layouts, images, and intelligent CSS3 media queries. The responsive feature first checks the screen size of the device and accordingly adjusts it to fit the screen without creating different layouts.

9. Do you think CSS3 is required in a Responsive website?

Yes, CSS3 is required in a responsive website. Because it makes for easier loading. It makes the website lucrative. Responsive websites use CSS3 and HTML both to load the site faster and fit on all devices' screens in a single layout.

10. Tell me a few of the CSS3 frameworks.

There are a few CSS3 frameworks, they are:

• Bootstrap, Fully responsive.
• Blueprint, Typography, and button plugins are available.
• YAML, Fully elastic and fluid.
• Foundation, Fluid, and responsive layout.
• YUI CSS3 Grid, fixed and fluid.

Conclusion

We hope you have liked our CSS3 Interview Question and Answers blog. It has a high probability of coming in for interviews. This CSS3 blog was a comprehensive list of frequently asked questions and answers in interviews. All the best for your interview.