---
id: 67d2fe63c8b0049ad7481021
title: What Is the Value of Using a CSS Preprocessor, and What Are Some Disadvantages?
challengeType: 19
dashedName: what-is-the-value-of-using-a-css-preprocessor-and-what-are-some-disadvantages
---

# --description--

A CSS preprocessor is a tool that extends standard CSS with powerful features like variables, mixins, nesting, and selector inheritance. 

Some of these features, like variables and nesting, are now supported or are getting more support in native CSS, and this trend is very likely to continue. However, earlier versions of native CSS did not support these features.

That is why CSS preprocessors became so widely used in the first place. They take the CSS rules and styles you write, along with their extended syntax, and compile them into a native CSS file that browsers can understand.

By using a CSS preprocessor, you can structure your CSS code in a more reusable and logical way. You will also have access to powerful features, like mixins, that are not directly supported by CSS.

Some of the most popular CSS preprocessors are Sass, Less, and Stylus.

Let's talk about Sass.

Sass stands for "Syntactically Awesome Style Sheets." It's compatible with all versions of CSS and maintained by a large community of developers.

Sass supports features like:

- Variables, so you can store and reuse values throughout the spreadsheet.

- Nested CSS rules, so you can create a visual hierarchy in your file.

- Modules, so you can split your styles into multiple stylesheets.

- Mixins, so you can reuse CSS declarations throughout your site.

- Inheritance, so multiple CSS selectors can share properties.

- And operators, for basic mathematical operations.

Sass also supports two syntaxes.

The SCSS syntax stands for Sassy CSS, which is a superset of CSS. This means that SCSS expands the basic syntax of CSS.

SCSS is the most common syntax that you'll use and find when working with Sass. It requires the use of curly braces (`{` and `}`) around CSS properties and semicolons (`;`) at the end of CSS declarations, just like native CSS.

These files have a `.scss` extension. Here is an example:

```scss
$primary-color: #3498eb;

header {
  background-color: $primary-color;
}
```

What you see here, at the top, is a variable defined in SCSS. This variable is used in the CSS rule below.

Let's compare SCSS with a less-frequently used syntax, the indented syntax. This is also known as the "Sass syntax" since it was Sass's original syntax.

This syntax relies on indentation to define the rules. Here is an example:

```scss
$primary-color: #3498eb

header
  background-color: $primary-color
```

Notice that there are no curly braces around the CSS rule, or semi-colons at the end of CSS declarations. At the top, you can also see a variable. Notice that its name starts with a dollar sign (`$`) in this syntax, which is different than native CSS variables, but works very similarly.

Sass also supports a powerful feature, called mixins. 

Mixins allow you to group multiple CSS properties and their values under the name and reuse that block of CSS code throughout your stylesheet.

This makes your CSS code less repetitive and easier to maintain because, if you change something in that block, the change is applied everywhere you use the mixin.

Since mixins can have custom and descriptive names, they can be helpful to understand what each block of CSS code does, which can make your stylesheets easier to understand.

And mixins also promote consistency in stylesheets by applying uniform styles.

This is an example of a mixin in SCSS syntax:

```scss
@mixin center-flex {
  display: flex;
  justify-content: center;
  align-items: center;
}
```

To define a mixin, you start by writing the `@mixin` at-rule, followed by the name of the mixin. In this case, the mixin is called `center-flex`. It has three CSS properties to center elements using Flexbox.

Then, once you have your mixin defined, you would use the `@include` at-rule to include those properties in a CSS rule. You just need to write `@include` followed by the name of the mixin. In this case, the name is `center-flex`:

```scss
section {
  @include center-flex;
  height: 500px;
  background-color: #3289a8;
}
```

This is the full code with the mixin and the CSS rule:

```scss
@mixin center-flex {
  display: flex;
  justify-content: center;
  align-items: center;
}

section {
  @include center-flex;
  height: 500px;
  background-color: #3289a8;
}
```

You can include the mixin in as many CSS rules as needed. If you need to make any changes, you would only need to change the mixin itself and the changes would be applied everywhere automatically. This example is in SCSS syntax. Notice that it has the curly braces and the semicolons.

Here is the equivalent in indented syntax, also known as Sass syntax, without the curly braces or semicolons:

```scss
@mixin center-flex
  display: flex
  justify-content: center
  align-items: center

section
  @include center-flex
  height: 500px
  background-color: #3289a8
```

And this is the compiled CSS code, what the browser will actually interpret after the file is compiled into native CSS:

```css
section {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 500px;
  background-color: #3289a8;
}
```

Notice that it includes the three mixin properties at the top: `display`, `justify-content`, and `align-items`.

This is only a simple example of what CSS preprocessors are capable of. They have many powerful features that are worth learning and applying in your daily workflow.

However, they do have potential disadvantages that you should be aware of.

First, CSS preprocessors have to compile the CSS rules into standard CSS. While the potential overhead of this compilation process is often minimal in terms of time and resources, it is something that you should consider for real-world projects.

Next, they can create debugging challenges, since browsers use the compiled CSS directly. Finding out what is generating a problematic style from the extended syntax can take a few extra steps when compared to standard CSS.

However, the advantages of CSS preprocessors usually outweigh their disadvantages, especially for complex projects. They can be very helpful for writing cleaner, reusable, less repetitive, and scalable CSS.

# --questions--

## --text--

Which of the following is NOT a common feature of CSS preprocessors? 

## --answers--

Variables for storing and reusing values.

### --feedback--

Think about the extended syntax of CSS preprocessors.

---

Nested CSS rules for reflecting HTML structure.

### --feedback--

Think about the extended syntax of CSS preprocessors.

---

Automatic optimization of CSS for improved performance.

---

Mixins for creating reusable blocks of CSS styles.

### --feedback--

Think about the extended syntax of CSS preprocessors.

## --video-solution--

3

## --text--

What is the main purpose of a CSS preprocessor?

## --answers--

To allow developers to write CSS that is directly understood by browsers.

### --feedback--

Think about how CSS preprocessors extend the capabilities of CSS.

---

To extend the capabilities of CSS with more powerful features.

---

To replace CSS entirely with a modern styling language.

### --feedback--

Think about how CSS preprocessors extend the capabilities of CSS.

---

To design web pages without writing code.

### --feedback--

Think about how CSS preprocessors extend the capabilities of CSS.

## --video-solution--

2

## --text--

What is the relationship between Sass and SCSS?

## --answers--

They are entirely different CSS preprocessors with very distinct syntax.

### --feedback--

Think about the two different syntaxes available for working with Sass.

---

SCSS is a newer version of Sass that has completely replaced the original syntax.

### --feedback--

Think about the two different syntaxes available for working with Sass.

---

SCSS is a syntax for Sass that is closer to standard CSS.

---

Sass is a library that can be used with SCSS to add more features.

### --feedback--

Think about the two different syntaxes available for working with Sass.

## --video-solution--

3
