Content blocks with @content in SASS - Mini Project: Build & Apply

Using Content Blocks with @content in Sass

📖 Scenario: You are creating a reusable button style in Sass. You want to allow different buttons to have custom inner styles or content blocks using @content. This helps keep your styles clean and flexible.

🎯 Goal: Build a Sass mixin called button-style that applies basic button styles and accepts a content block with @content to add extra styles inside the button.

📋 What You'll Learn

Create a mixin named button-style with basic button styles

Use @content inside the mixin to allow custom inner styles

Include the mixin in a class .btn-primary and add extra styles using the content block

Ensure the final CSS styles the button with base and custom styles

💡 Why This Matters

🌍 Real World

Using @content in Sass mixins helps create flexible, reusable style blocks for UI components like buttons, cards, or alerts.

💼 Career

Front-end developers often write Sass mixins with @content to keep CSS DRY and maintainable while allowing customization.

1

Create the button-style mixin with base styles

Write a Sass mixin named button-style that sets padding to 1rem 2rem, border-radius to 0.5rem, and font-weight to bold.

SASS

# Create the button-style mixin with padding, border-radius, and font-weight
@mixin button-style {
  // Your code here
}

Hint

Use @mixin button-style { ... } and add the three CSS properties inside.

2

Add @content inside the button-style mixin

Inside the button-style mixin, add @content after the base styles to allow custom styles to be inserted.

SASS

@mixin button-style {
  padding: 1rem 2rem;
  border-radius: 0.5rem;
  font-weight: bold;
  // Add @content here
}

Hint

Place @content; inside the mixin after the base styles.

3

Include the button-style mixin in .btn-primary class

Create a CSS class .btn-primary and include the button-style mixin inside it using @include button-style.

SASS

@mixin button-style {
  padding: 1rem 2rem;
  border-radius: 0.5rem;
  font-weight: bold;
  @content;
}

.btn-primary {
  // Include button-style mixin here
}

Hint

Use @include button-style { } inside the .btn-primary block.

4

Add custom background and color styles inside the mixin content block

Inside the @include button-style block in .btn-primary, add background-color: #007bff; and color: white; to style the button's background and text color.

SASS

@mixin button-style {
  padding: 1rem 2rem;
  border-radius: 0.5rem;
  font-weight: bold;
  @content;
}

.btn-primary {
  @include button-style {
    // Add background-color and color here
  }
}

Hint

Inside the content block, add background-color: #007bff; and color: white;.

Practice

1. What is the main purpose of @content in Sass?

easy

A. To pass custom styles into a mixin for flexible reuse

B. To define variables inside a mixin

C. To import external CSS files

D. To create loops in Sass

Solution

1. Step 1: Understand what @content does

   @content allows you to insert custom CSS blocks inside a mixin, making it flexible.

2. Step 2: Compare with other options

   Variables, imports, and loops are different Sass features unrelated to @content.

3. Final Answer:

   To pass custom styles into a mixin for flexible reuse -> Option A

4. Quick Check:

   @content = custom styles in mixin [OK]

Hint: Remember: @content inserts custom styles inside mixins [OK]

Common Mistakes:

• Confusing @content with variables or imports
• Thinking @content creates loops
• Assuming @content is for defining selectors

2. Which of the following is the correct syntax to use @content inside a mixin?

easy

A. @mixin example { @include content; }

B. @mixin example { content(); }

C. @mixin example { @content; }

D. @mixin example { content; }

Solution

1. Step 1: Recall the syntax for content blocks

   Inside a mixin, @content; is used to insert the passed block.

2. Step 2: Check each option

   Only @mixin example { @content; } uses @content; correctly with the semicolon.

3. Final Answer:

   @mixin example { @content; } -> Option C

4. Quick Check:

   Correct syntax uses @content; inside mixin [OK]

Hint: Use @content; with a semicolon inside mixins [OK]

Common Mistakes:

• Omitting the @ symbol before content
• Using parentheses like a function call
• Forgetting the semicolon after @content

3. What will be the output CSS of this Sass code?

@mixin card {
  border: 1px solid black;
  padding: 1rem;
  @content;
}

.box {
  @include card {
    background-color: yellow;
  }
}

medium

A. .box { border: 1px solid black; padding: 1rem; } .box { background-color: yellow; }

B. .box { border: 1px solid black; padding: 1rem; background-color: yellow; }

C. .box { background-color: yellow; }

D. Syntax error, no output

Solution

1. Step 1: Understand mixin with @content

   The mixin card adds border and padding, then inserts the passed block with @content.

2. Step 2: Check how .box includes the mixin

   The block inside @include card { ... } adds background-color: yellow; inside the mixin's content.

3. Final Answer:

   .box { border: 1px solid black; padding: 1rem; background-color: yellow; } -> Option B

4. Quick Check:

   Mixin + @content block = combined styles [OK]

Hint: Mixin styles + @content block styles combine inside selector [OK]

Common Mistakes:

• Thinking @content styles appear outside the selector
• Expecting separate CSS blocks for mixin and content
• Assuming syntax error due to block usage

4. Identify the error in this Sass code using @content:

@mixin highlight {
  background: yellow;
  @content
}

.text {
  @include highlight {
    color: red;
  }
}

medium

A. Missing semicolon after @content

B. Mixin name should be @content

C. Cannot use blocks with @include

D. Background property is invalid

Solution

1. Step 1: Check syntax of @content inside mixin

   @content must end with a semicolon to be valid.

2. Step 2: Verify other parts

   Mixin name and block usage are correct; background property is valid CSS.

3. Final Answer:

   Missing semicolon after @content -> Option A

4. Quick Check:

   @content requires semicolon [OK]

Hint: Always put semicolon after @content inside mixins [OK]

Common Mistakes:

• Omitting semicolon after @content
• Confusing mixin and content names
• Thinking block usage with @include is invalid

5. You want to create a reusable button style mixin that allows custom hover styles using @content. Which Sass code correctly achieves this?

hard

A. @mixin button { padding: 1rem; border: none; @content; &:hover { @content; } }

B. @mixin button { padding: 1rem; border: none; @content; } .btn:hover { @content; }

C. @mixin button { padding: 1rem; border: none; } .btn { @include button; &:hover { @content; } }

D. @mixin button { padding: 1rem; border: none; @content; &:hover { @content; } } .btn { @include button { color: blue; &:hover { color: red; } } }

Solution

1. Step 1: Understand the goal

   Create a mixin that sets base button styles and allows custom styles including hover via @content.

2. Step 2: Analyze each option

   @mixin button { padding: 1rem; border: none; @content; &:hover { @content; } } .btn { @include button { color: blue; &:hover { color: red; } } } defines the mixin with @content inside and inside &:hover, then includes it with a block that passes normal and hover styles. This correctly applies custom hover styles.

3. Step 3: Why others fail

   @mixin button { padding: 1rem; border: none; @content; &:hover { @content; } } tries to use @content twice in the mixin without passing blocks properly. @mixin button { padding: 1rem; border: none; @content; } .btn:hover { @content; } applies hover styles outside the mixin, losing reusability. @mixin button { padding: 1rem; border: none; } .btn { @include button; &:hover { @content; } } misuses @content outside mixin context.

4. Final Answer:

   @mixin button { padding: 1rem; border: none; @content; &:hover { @content; } } .btn { @include button { color: blue; &:hover { color: red; } } } -> Option D

5. Quick Check:

   Mixin with @content block for hover = @mixin button { padding: 1rem; border: none; @content; &:hover { @content; } } .btn { @include button { color: blue; &:hover { color: red; } } } [OK]

Hint: Pass hover styles inside @include block with nested &:hover [OK]

Common Mistakes:

• Using @content outside mixin
• Trying to call @content multiple times without blocks
• Defining hover styles outside mixin losing flexibility