@apply for extracting patterns in Tailwind - Mini Project: Build & Apply

Extracting Patterns with Tailwind CSS @apply

📖 Scenario: You are building a simple webpage with multiple buttons that share the same style. Instead of repeating the same Tailwind CSS classes on each button, you want to extract the common styles into a reusable CSS class using the @apply directive.

🎯 Goal: Create a CSS class called .btn that uses @apply to include common Tailwind utility classes. Then use this class on multiple buttons in your HTML to keep your code clean and consistent.

📋 What You'll Learn

Create a CSS class named .btn in a styles.css file

Use @apply inside .btn to add Tailwind utility classes for padding, background color, text color, rounded corners, and hover effect

Add three buttons in the HTML that use the btn class

Ensure the buttons have consistent styling and a hover effect

💡 Why This Matters

🌍 Real World

Extracting common styles into reusable classes helps keep your CSS clean and maintainable, especially in projects with many similar elements.

💼 Career

Knowing how to use Tailwind's @apply directive is valuable for frontend developers to write efficient, scalable styles and collaborate on large codebases.

1

Create the HTML structure with three buttons

Write the basic HTML skeleton with a <main> section containing three <button> elements. Each button should have the text Button 1, Button 2, and Button 3 respectively. Do not add any classes yet.

Tailwind

    
    
    Button Styles
    


    
        
    

Hint

Use three <button> tags inside the <main> element with the exact texts.

2

Create a CSS class .btn with Tailwind utility classes using @apply

In the styles.css file, create a CSS class called .btn. Inside it, use the @apply directive to add these Tailwind classes exactly: px-4, py-2, bg-blue-600, text-white, rounded, and hover:bg-blue-700.

Tailwind

    
    
    Button Styles
    


    
        Button 1
        Button 2
        Button 3
    



/* In styles.css file */

/* Create .btn class and use @apply with Tailwind classes */
/* Your code here */

Hint

Write a CSS class .btn and inside it use @apply with the exact Tailwind classes separated by spaces.

3

Add the btn class to all three buttons in the HTML

Modify the three <button> elements in the HTML to include the class attribute with the value btn. For example, <button class="btn">Button 1</button>.

Tailwind

    
    
    Button Styles
    


    
        
        Button 1
        Button 2
        Button 3
    



/* In styles.css file */

.btn {
    @apply px-4 py-2 bg-blue-600 text-white rounded hover:bg-blue-700;
}

Hint

Add class="btn" inside each <button> tag.

4

Add accessibility and responsive spacing to the buttons

Add an aria-label attribute to each button with the same text as the button's visible text (e.g., aria-label="Button 1"). Also, add a Tailwind class space-x-4 to the <main> element to add horizontal spacing between the buttons.

Tailwind

    
    
    Button Styles
    


    
    
        Button 1
        Button 2
        Button 3
    



/* In styles.css file */

.btn {
    @apply px-4 py-2 bg-blue-600 text-white rounded hover:bg-blue-700;
}

Hint

Add class="space-x-4" to the <main> tag and add aria-label attributes to each button with matching text.

Practice

1. What is the main purpose of using @apply in Tailwind CSS?

easy

A. To create animations in Tailwind CSS

B. To add JavaScript functionality to Tailwind classes

C. To import external CSS files into Tailwind

D. To combine multiple utility classes into one reusable custom class

Solution

1. Step 1: Understand what @apply does

   @apply lets you write multiple Tailwind utility classes inside a CSS rule to create a single custom class.

2. Step 2: Identify the main use

   This helps reuse styles and keep code tidy by combining utilities into one class.

3. Final Answer:

   To combine multiple utility classes into one reusable custom class -> Option D

4. Quick Check:

   @apply combines utilities = C [OK]

Hint: Remember: @apply bundles utilities into one class [OK]

Common Mistakes:

• Thinking @apply adds JavaScript
• Confusing @apply with animation creation
• Assuming @apply imports CSS files

2. Which of the following is the correct syntax to use @apply inside a CSS file?

easy

A. .btn { @apply text-white bg-blue-500 px-4 py-2; }

B. .btn { apply: text-white bg-blue-500 px-4 py-2; }

C. .btn { @use text-white bg-blue-500 px-4 py-2; }

D. .btn { apply(@text-white, @bg-blue-500); }

Solution

1. Step 1: Recall the correct @apply syntax

   The correct way is to write @apply followed by utility classes inside a CSS rule block.

2. Step 2: Check each option

   Only .btn { @apply text-white bg-blue-500 px-4 py-2; } uses @apply correctly with utility classes separated by spaces.

3. Final Answer:

   .btn { @apply text-white bg-blue-500 px-4 py-2; } -> Option A

4. Quick Check:

   Correct @apply syntax = A [OK]

Hint: Look for '@apply' keyword followed by utilities inside braces [OK]

Common Mistakes:

• Using 'apply:' instead of '@apply'
• Using '@use' or other incorrect keywords
• Trying to call @apply like a function

3. Given this CSS code using @apply:

.card {
  @apply p-6 bg-white rounded-lg shadow-md;
}

What visual styles will the .card class have?

medium

A. No padding, transparent background, rounded corners, and large shadow

B. Padding of 6px, black background, square corners, and no shadow

C. Padding of 1.5rem, white background, rounded corners, and medium shadow

D. Padding of 6rem, gray background, rounded corners, and small shadow

Solution

1. Step 1: Understand each utility class

   p-6 means padding 1.5rem, bg-white sets white background, rounded-lg adds large rounded corners, shadow-md adds medium shadow.

2. Step 2: Match these styles to options

   Padding of 1.5rem, white background, rounded corners, and medium shadow correctly describes these styles. Others have wrong padding sizes or colors.

3. Final Answer:

   Padding of 1.5rem, white background, rounded corners, and medium shadow -> Option C

4. Quick Check:

   p-6 + bg-white + rounded-lg + shadow-md = A [OK]

Hint: Know Tailwind spacing and color names to decode @apply output [OK]

Common Mistakes:

• Confusing padding units (px vs rem)
• Mixing up background colors
• Misunderstanding shadow sizes

4. What is wrong with this CSS using @apply?

.btn {
  @apply text-white bg-blue-500 px-4 py-2;
  @apply rounded-lg;
  color: red;
}

medium

A. The syntax is invalid because @apply must be last

B. Multiple @apply statements should be combined into one

C. The color property conflicts with @apply and causes error

D. You cannot use @apply with padding classes

Solution

1. Step 1: Check usage of multiple @apply

   Tailwind allows multiple @apply but best practice is to combine them for clarity and to avoid duplication.

2. Step 2: Analyze other options

   @apply works with padding, color property is valid CSS and does not cause error, and @apply can be anywhere inside the rule.

3. Final Answer:

   Multiple @apply statements should be combined into one -> Option B

4. Quick Check:

   Combine @apply classes for cleaner CSS = D [OK]

Hint: Combine all utilities in one @apply for neat CSS [OK]

Common Mistakes:

• Thinking @apply can't be used multiple times
• Assuming color property conflicts with @apply
• Believing @apply must be last in CSS block

5. You want to create a reusable button style in Tailwind using @apply that has white text, blue background, padding, rounded corners, and a hover effect that darkens the background. Which CSS snippet correctly achieves this?

hard

A. .btn {
@apply text-white bg-blue-500 px-4 py-2 rounded;
&:hover { @apply bg-blue-700; }
}

B. .btn {
@apply text-white bg-blue-500 px-4 py-2 rounded hover:bg-blue-700;
}

C. .btn {
@apply text-white bg-blue-500 px-4 py-2 rounded;
:hover { @apply bg-blue-700; }
}

D. .btn {
@apply text-white bg-blue-500 px-4 py-2 rounded;
hover: { @apply bg-blue-700; }
}

Solution

1. Step 1: Understand hover styling with @apply

   To apply hover styles with @apply, you must nest inside a CSS hover selector like &:hover in your CSS.

2. Step 2: Check each option's hover syntax

   .btn { @apply text-white bg-blue-500 px-4 py-2 rounded; &:hover { @apply bg-blue-700; } } correctly uses &:hover { @apply bg-blue-700; }. .btn { @apply text-white bg-blue-500 px-4 py-2 rounded hover:bg-blue-700; } tries to use hover:bg-blue-700 inside @apply which is invalid. Options C and D have incorrect hover selector syntax.

3. Final Answer:

   .btn { @apply text-white bg-blue-500 px-4 py-2 rounded; &:hover { @apply bg-blue-700; } } -> Option A

4. Quick Check:

   Use &:hover with @apply for hover styles = B [OK]

Hint: Use &:hover { @apply ... } for hover styles in CSS [OK]

Common Mistakes:

• Trying to use hover: prefix inside @apply
• Using :hover without & in nested CSS
• Incorrect hover selector syntax causing errors