Case File · CSS

Variables

Variables

Variables is a core part of CSS. In this case file you'll learn what it is, why it matters, and how to use it in real code.

Understanding variables well means you can read other people's CSS code with confidence, and avoid the most common beginner mistakes in this area.

Key points:

  • What variables means in the context of CSS
  • A minimal example you can run or read in the playground on the right
  • A common mistake to avoid when working with variables
/* CSS: Variables */
body {
  font-family: sans-serif;
  background: #0B0F17;
  color: #E5E7EB;
}

.card {
  padding: 1rem;
  border-radius: 0.75rem;
  border: 1px solid #22D3EE55;
}

Tip: Try changing a value in the code on the right and re-running it — small experiments are the fastest way to build real intuition for variables.

The Lab

CSS Case File Quiz

Score 70% or higher to unlock your Agent Certification.

1. What is CSS primarily used for?

2. Which of these is a real chapter covered in the CSS case file?

3. In The Lab playground, what does the "Reset" button do?

4. What score do you need on this topic's quiz to unlock your Agent Certification?