Content blocks with @content in SASS - Practice Problems & Coding Challenges

Challenge - 5 Problems

📝 Syntax

intermediate

What is the output CSS of this Sass code using @content?

Consider the following Sass code. What CSS does it produce when compiled?

@mixin card() {
  border: 1px solid #ccc;
  padding: 1rem;
  @content;
  background: white;
}

.container {
  @include card() {
    box-shadow: 0 0 5px rgba(0,0,0,0.1);
  }
}

SASS

@mixin card() {
  border: 1px solid #ccc;
  padding: 1rem;
  @content;
  background: white;
}

.container {
  @include card() {
    box-shadow: 0 0 5px rgba(0,0,0,0.1);
  }
}

A

.container {
  border: 1px solid #ccc;
  padding: 1rem;
  background: white;
  box-shadow: 0 0 5px rgba(0,0,0,0.1);
}

B

.container {
  border: 1px solid #ccc;
  padding: 1rem;
  background: white;
}
.container {
  box-shadow: 0 0 5px rgba(0,0,0,0.1);
}

C

.container {
  border: 1px solid #ccc;
  padding: 1rem;
  box-shadow: 0 0 5px rgba(0,0,0,0.1);
  background: white;
}

D

.container {
  border: 1px solid #ccc;
  padding: 1rem;
  background: white;
}
.box-shadow {
  box-shadow: 0 0 5px rgba(0,0,0,0.1);
}

💡 Hint

Remember that @content inserts the block exactly where it is placed inside the mixin.

The @content block is inserted exactly where @content is called inside the mixin. So the box-shadow property appears between padding and background inside the .container rule.

🧠 Conceptual

intermediate

What happens if @content is missing inside a mixin?

Given this Sass mixin:

@mixin highlight() {
  background-color: yellow;
  @content;
  border: 1px solid orange;
}

What will happen if you include it without providing a content block like this?

.note {
  @include highlight();
}

SASS

@mixin highlight() {
  background-color: yellow;
  @content;
  border: 1px solid orange;
}

.note {
  @include highlight();
}

A The .note class will have yellow background and orange border, but no extra styles inside.

B It will cause a syntax error because @content is required.

C The mixin will be ignored and .note will have no styles.

D The .note class will be empty because @content is missing.

💡 Hint

Think about what @content does when no block is passed.

If no content block is passed, @content is simply ignored and the rest of the mixin styles apply normally.

❓ selector

advanced

How does @content affect nested selectors inside a mixin?

Look at this Sass code:

@mixin button-style() {
  padding: 0.5rem 1rem;
  border-radius: 0.25rem;
  @content;
  &:hover {
    background-color: #eee;
  }
}

.btn {
  @include button-style() {
    background-color: blue;
    color: white;
  }
}

What CSS will be generated for the .btn:hover selector?

SASS

@mixin button-style() {
  padding: 0.5rem 1rem;
  border-radius: 0.25rem;
  @content;
  &:hover {
    background-color: #eee;
  }
}

.btn {
  @include button-style() {
    background-color: blue;
    color: white;
  }
}

A

.btn:hover {
  background-color: blue;
  color: white;
}

B

.btn:hover {
  background-color: #eee;
}

C

.btn:hover {
  background-color: #eee;
  background-color: blue;
  color: white;
}

D No .btn:hover selector is generated.

💡 Hint

Remember that @content inserts styles inside the main selector, but &:hover is a nested selector inside the mixin.

The &:hover block inside the mixin creates a .btn:hover selector with background-color #eee. The @content block inserts styles inside .btn, not inside :hover.

❓ rendering

advanced

What visual effect will this Sass code produce?

Given this Sass code:

@mixin card() {
  border: 2px solid black;
  padding: 1rem;
  background: white;
  @content;
}

.article {
  @include card() {
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    border-radius: 0.5rem;
  }
}

What will the .article box look like in a browser?

SASS

@mixin card() {
  border: 2px solid black;
  padding: 1rem;
  background: white;
  @content;
}

.article {
  @include card() {
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    border-radius: 0.5rem;
  }
}

A A white box with a black border, some padding, a subtle shadow, and rounded corners.

B A white box with a black border and padding but no shadow or rounded corners.

C A box with only shadow and rounded corners but no border or padding.

D A transparent box with no visible border, shadow, or padding.

💡 Hint

The @content block adds extra styles inside the box.

The mixin sets border, padding, and background. The @content block adds box-shadow and border-radius inside the same selector, so all styles combine visually.

❓ accessibility

expert

How can @content help improve accessibility in Sass components?

You want to create a reusable button style mixin that allows adding accessible focus styles via @content. Which approach below correctly uses @content to insert focus styles while keeping the base styles consistent?

@mixin accessible-button() {
  padding: 0.75rem 1.5rem;
  border: none;
  background-color: #007BFF;
  color: white;
  cursor: pointer;
  @content;
}

How should you include this mixin to add a visible focus outline for keyboard users?

SASS

@mixin accessible-button() {
  padding: 0.75rem 1.5rem;
  border: none;
  background-color: #007BFF;
  color: white;
  cursor: pointer;
  @content;
}

.button {
  @include accessible-button() {
    &:focus-visible {
      outline: 3px solid #FFD700;
      outline-offset: 2px;
    }
  }
}

A Add focus styles outside the mixin, separately targeting .button:focus-visible.

B Use JavaScript to add focus styles instead of Sass @content.

C Add focus styles inside the mixin before @content without using a content block.

D Include the mixin with a content block that adds &:focus-visible styles inside the button selector.

💡 Hint

Think about how @content lets you add custom nested selectors inside a reusable style block.

Using @content inside the mixin allows you to add custom nested selectors like &:focus-visible when including the mixin, keeping all related styles together and improving maintainability and accessibility.

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