Grid system mixin from scratch in SASS - Mini Project: Build & Apply

Grid system mixin from scratch

📖 Scenario: You are building a simple grid system for a website layout. This grid system will help arrange content in columns that adapt to different screen sizes. You will create a Sass mixin that generates CSS grid columns based on the number of columns you want.

🎯 Goal: Create a Sass mixin called grid-column that takes a number of columns as input and sets the width of the element accordingly. Use this mixin to style grid items so they fit nicely in a 12-column grid layout.

📋 What You'll Learn

Create a Sass variable for the total number of columns in the grid (12).

Write a mixin named grid-column that accepts a parameter $cols for the number of columns to span.

The mixin should calculate the width as a percentage based on $cols and the total columns.

Use the mixin to style grid items with different column spans.

Ensure the grid container uses CSS Flexbox to arrange items in a row.

💡 Why This Matters

🌍 Real World

Grid systems are used in web design to create clean, organized layouts that adapt to different screen sizes. This project shows how to build a simple grid system from scratch using Sass.

💼 Career

Understanding how to create and use mixins for layout helps front-end developers write reusable, maintainable CSS and build responsive websites efficiently.

1

Set up the total columns variable

Create a Sass variable called $total-columns and set it to 12 to represent the total number of columns in the grid.

SASS

$total-columns: 12;
// Your code here

Hint

Use $total-columns: 12; to define the total columns.

2

Create the grid-column mixin

Write a Sass mixin named grid-column that takes a parameter $cols. Inside the mixin, calculate the width as ($cols / $total-columns) * 100% and set it as the element's width.

SASS

$total-columns: 12;

@mixin grid-column($cols) {
  // Your code here
}

Hint

Use @mixin grid-column($cols) { width: ($cols / $total-columns) * 100%; }.

3

Set up the grid container with Flexbox

Create a CSS class .grid-container that uses Flexbox with display: flex; and allows wrapping with flex-wrap: wrap;.

SASS

$total-columns: 12;

@mixin grid-column($cols) {
  width: ($cols / $total-columns) * 100%;
}

.grid-container {
  // Your code here
}

Hint

Use display: flex; and flex-wrap: wrap; inside .grid-container.

4

Use the mixin to style grid items

Create CSS classes .col-4 and .col-8 that include the grid-column mixin with $cols set to 4 and 8 respectively.

SASS

$total-columns: 12;

@mixin grid-column($cols) {
  width: ($cols / $total-columns) * 100%;
}

.grid-container {
  display: flex;
  flex-wrap: wrap;
}

.col-4 {
  // Your code here
}

.col-8 {
  // Your code here
}

Hint

Use @include grid-column(4); in .col-4 and @include grid-column(8); in .col-8.

Practice

1. What is the main purpose of a grid system mixin in Sass?

easy

A. To create flexible column layouts with reusable code

B. To add colors to text elements

C. To write JavaScript functions inside Sass

D. To load external fonts automatically

Solution

1. Step 1: Understand the role of mixins in Sass

   Mixins let you reuse code blocks with parameters to customize styles.

2. Step 2: Identify what a grid system mixin does

   A grid system mixin helps create column layouts that adapt easily by changing parameters.

3. Final Answer:

   To create flexible column layouts with reusable code -> Option A

4. Quick Check:

   Grid mixin = flexible columns [OK]

Hint: Grid mixins simplify layout by reusing column code [OK]

Common Mistakes:

• Confusing mixins with variables
• Thinking mixins add colors only
• Assuming mixins run JavaScript

2. Which of the following is the correct way to define a simple grid mixin with columns and gap parameters in Sass?

easy

A. @mixin grid($columns, $gap) { display: flex; columns: $columns; gap: $gap; }

B. @mixin grid($columns, $gap) { display: block; grid-columns: $columns; grid-gap: $gap; }

C. @mixin grid($columns, $gap) { display: grid; grid-template-columns: repeat($columns, 1fr); gap: $gap; }

D. @mixin grid($columns, $gap) { display: grid; columns: $columns; gap: $gap; }

Solution

1. Step 1: Check the display property for grid layout

   Grid layouts require display: grid;, not flex or block.

2. Step 2: Verify grid-template-columns and gap syntax

   Using grid-template-columns: repeat($columns, 1fr); sets equal columns, and gap: $gap; sets spacing.

3. Final Answer:

   @mixin grid($columns, $gap) { display: grid; grid-template-columns: repeat($columns, 1fr); gap: $gap; } -> Option C

4. Quick Check:

   Grid needs display:grid and repeat() [OK]

Hint: Use display:grid and repeat() for columns [OK]

Common Mistakes:

• Using display:flex instead of grid
• Using incorrect property names like columns
• Missing repeat() function for columns

3. Given this Sass mixin and usage:

@mixin grid($cols, $gap) {
  display: grid;
  grid-template-columns: repeat($cols, 1fr);
  gap: $gap;
}

.container {
  @include grid(3, 2rem);
}

What CSS will be generated for .container?

medium

A. .container { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }

B. .container { display: flex; columns: 3; gap: 2rem; }

C. .container { display: grid; grid-template-columns: 3fr; gap: 2rem; }

D. .container { display: block; grid-template-columns: repeat(3, 1fr); gap: 2rem; }

Solution

1. Step 1: Understand mixin parameters and usage

   The mixin sets grid display, columns with repeat, and gap using passed values 3 and 2rem.

2. Step 2: Translate Sass mixin to CSS output

   Including the mixin with (3, 2rem) generates CSS with display: grid;, grid-template-columns: repeat(3, 1fr);, and gap: 2rem;.

3. Final Answer:

   .container { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; } -> Option A

4. Quick Check:

   Mixin params = CSS properties [OK]

Hint: Repeat columns with 1fr for equal width [OK]

Common Mistakes:

• Confusing flex with grid display
• Writing grid-template-columns: 3fr instead of repeat()
• Using display:block by mistake

4. Identify the error in this Sass grid mixin:

@mixin grid($cols, $gap) {
  display: grid;
  grid-template-columns: repeat($cols 1fr);
  gap: $gap;
}

medium

A. gap property is invalid in grid layouts

B. Using display:flex instead of display:grid

C. Mixin parameters should be $columns and $gaps

D. Missing comma between $cols and 1fr in repeat() function

Solution

1. Step 1: Check syntax of repeat() function

   The repeat() function requires a comma between the number and the size, like repeat($cols, 1fr).

2. Step 2: Verify other properties

   Display is correctly set to grid, and gap is valid for grid layouts.

3. Final Answer:

   Missing comma between $cols and 1fr in repeat() function -> Option D

4. Quick Check:

   repeat() needs comma [OK]

Hint: Always put a comma inside repeat() between count and size [OK]

Common Mistakes:

• Omitting comma in repeat()
• Confusing display:flex with grid
• Thinking gap is invalid in grid

5. You want a responsive grid mixin that changes columns based on screen width. Which Sass code correctly adds a media query inside the mixin to set 2 columns on screens smaller than 600px and 4 columns otherwise?

hard

A. @mixin responsive-grid($gap) { display: grid; grid-template-columns: repeat(2, 1fr); gap: $gap; @media (min-width: 600px) { grid-template-columns: repeat(4, 1fr); } }

B. @mixin responsive-grid($gap) { display: grid; grid-template-columns: repeat(4, 1fr); gap: $gap; @media (max-width: 600px) { grid-template-columns: repeat(2, 1fr); } }

C. @mixin responsive-grid($gap) { display: flex; gap: $gap; @media (max-width: 600px) { flex-direction: column; } }

D. @mixin responsive-grid($gap) { display: grid; grid-template-columns: repeat(4, 1fr); gap: $gap; @media (min-width: 600px) { grid-template-columns: repeat(2, 1fr); } }

Solution

1. Step 1: Set default columns for large screens

   The mixin sets 4 columns by default using repeat(4, 1fr).

2. Step 2: Add media query for smaller screens

   Inside @media (max-width: 600px), columns change to 2 with repeat(2, 1fr).

3. Step 3: Confirm display and gap properties

   Display is grid and gap uses the parameter, which is correct.

4. Final Answer:

   @mixin responsive-grid($gap) { display: grid; grid-template-columns: repeat(4, 1fr); gap: $gap; @media (max-width: 600px) { grid-template-columns: repeat(2, 1fr); } } -> Option B

5. Quick Check:

   Default 4 cols, max-width 600px = 2 cols [OK]

Hint: Use max-width media query for smaller screens [OK]

Common Mistakes:

• Using min-width instead of max-width for small screens
• Setting flex display instead of grid
• Reversing column counts in media query