5 Essential CSS Interview Questions *

Toptal sourced essential questions that the best CSS developers and engineers can answer. Driven from our community, we encourage experts to submit questions and offer feedback.

Hire a Top CSS Developer Now
Toptal logois an exclusive network of the top freelance software developers, designers, finance experts, product managers, and project managers in the world. Top companies hire Toptal freelancers for their most important projects.

Interview Questions


Explain the CSS “box model” and the layout components that it consists of.

Provide some usage examples.

View answer

The CSS box model is a rectangular layout paradigm for HTML elements that consists of the following:

  • Content - The content of the box, where text and images appear
  • Padding - A transparent area surrounding the content (i.e., the amount of space between the border and the content)
  • Border - A border surrounding the padding (if any) and content
  • Margin - A transparent area surrounding the border (i.e., the amount of space between the border and any neighboring elements)

Each of these properties can be specified independently for each side of the element (i.e., top, right, bottom, left) or fewer values can be specified to apply to multiple sides. For example:

/*       top   right  bottom left  */
padding: 25px  50px   75px   100px;

/* same padding on all 4 sides: */
padding: 25px;

/* top/bottom padding 25px; right/left padding 50px */
padding: 25px 50px;

/* top padding 25px; right/left padding 50px; bottom padding 75px */
padding: 25px 50px 75px;

Explain what elements will match each of the following CSS selectors:

  1. div, p
  2. div p
  3. div > p
  4. div + p
  5. div ~ p
View answer
  1. div, p - Selects all <div> elements and all <p> elements
  2. div p - Selects all <p> elements that are anywhere inside a <div> element
  3. div > p - Selects all <p> elements where the immediate parent is a <div> element
  4. div + p - Selects all <p> elements that are placed immediately after a <div> element
  5. div ~ p - Selects all <p> elements that are anywhere preceded by a <div> element

Explain the meaning of each of these CSS units for expressing length:

  • cm
  • em
  • in
  • mm
  • pc
  • pt
  • px
View answer
  • cm - centimeters
  • em - elements (i.e., relative to the font-size of the element; e.g., 2 em means 2 times the current font size)
  • in - inches
  • mm - millimeters
  • pc - picas (1 pc = 12 pt = 1/6th of an inch)
  • pt - points (1 pt = 1/72nd of an inch)
  • px - pixels (1 px = 1/96th of an inch)

Apply to Join Toptal's Development Network

and enjoy reliable, steady, remote Freelance CSS Developer Jobs

Apply as a Freelancer

In CSS3, how would you select:

  • Every <a> element whose href attribute value begins with “https”.
  • Every <a> element whose href attribute value ends with “.pdf”.
  • Every <a> element whose href attribute value contains the substring “css”.
View answer

Select every <a> element whose href attribute value begins with “https”:


Select every <a> element whose href attribute value ends with “.pdf”:


Select every <a> element whose href attribute value contains the substring “css”:


Given the following HTML:

<div id="page">
  <h1>Heading Title</h1>
  <h2>Subheading Title</h2>
  <h2>Subheading Title</h2>
  <h1>Heading Title</h1>
  <h2>Subheading Title</h2>
  <h1>Heading Title</h1>

How could you use CSS to achieve the following automatic numbering:

1) Heading Title
1.1) Subheading Title
1.2) Subheading Title

2) Heading Title
2.1) Subheading Title

3) Heading Title

View answer

The following CSS will achieve this type of automatic numbering:

#page {
  counter-reset: heading;

h1:before {
  content: counter(heading)") ";
  counter-increment: heading;

h1 {
  counter-reset: subheading;

h2:before {
  content: counter(heading)"." counter(subheading)") ";
  counter-increment: subheading;

There is more to interviewing than tricky technical questions, so these are intended merely as a guide. Not every “A” candidate worth hiring will be able to answer them all, nor does answering them all guarantee an “A” candidate. At the end of the day, hiring remains an art, a science — and a lot of work.

Why Toptal

Tired of interviewing candidates? Not sure what to ask to get you a top hire?

Let Toptal find the best people for you.

Hire a Top CSS Developer Now

Our Exclusive Network of CSS Developers

Looking to land a job as a CSS Developer?

Let Toptal find the right job for you.

Apply as a CSS Developer

Job Opportunities From Our Network

Submit an interview question

Submitted questions and answers are subject to review and editing, and may or may not be selected for posting, at the sole discretion of Toptal, LLC.

* All fields are required

Looking for CSS Developers?

Looking for CSS Developers? Check out Toptal’s CSS developers.

Giulia Cardieri

Freelance CSS Developer
Toptal Member Since September 19, 2018

Giulia is a creative and detail-oriented freelancer with a passion for front-end development and UI/UX design. She has over six years of experience developing web applications for professional, academic, and personal projects. Giulia is a CSS enthusiast, and she is always learning new technologies. She is a good communicator and values empathy between co-workers.

Show More

Abhilash Sandi

Freelance CSS Developer
United States
Toptal Member Since December 20, 2021

Abhilash is a senior software engineer with 10+ years of experience, specializing in React front-end development for the past three years. His technical strengths include React, JavaScript, Node.js, Angular, HTML, and CSS. Abhilash's industry experience is backed by a bachelor's degree in computer science from the National Institute of Technology in Nagpur, India.

Show More

Mike Jarosch

Freelance CSS Developer
United States
Toptal Member Since June 21, 2021

Mike has two decades of experience with all phases of development as part of an agile team; including gathering requirements, creating technical designs, developing, testing, documenting, and ongoing support. He specializes in a wide range of languages (C#, JavaScript, HTML/CSS), technologies (ASP>NET Core, jQuery, Sitecore), platforms (Azure, IIS, MS SQL Server), and tools (VS Code, Git, Node.js).

Show More

Toptal Connects the Top 3% of Freelance Talent All Over The World.

Join the Toptal community.

Learn more