Building Dynamic Styles with Control Structures

Tutorial 4 of 5

1. Introduction

1.1 Tutorial's Goal

This tutorial aims to demonstrate how to build dynamic, responsive styles using control structures in SASS/SCSS. By using control structures, we can create styles that adapt to changes in the environment, enhancing our web page's responsiveness and interactivity.

1.2 Learning Outcome

Upon completion of this tutorial, you will be able to:
- Understand SASS/SCSS control structures
- Implement dynamic styles using these control structures
- Build more responsive and interactive web pages

1.3 Prerequisites

Basic understanding of HTML, CSS, and SASS/SCSS is required to follow along with this tutorial.

2. Step-by-Step Guide

2.1 Understanding Control Structures

Control structures are used to perform different actions based on different conditions. In SASS/SCSS, we primarily use @if, @for, @each, and @while as our control structures.

2.2 Implementing Dynamic Styles

Let's take a closer look at each control structure and how we can use them to create dynamic styles.

2.2.1 @if

The @if directive takes an expression and outputs the nested styles if the expression is true.

$p: true;

div {
  @if $p {
    color: blue;
  } @else {
    color: red;
  }
}

In this snippet, the div's color will be blue if $p is true. Otherwise, it will be red.

2.2.2 @for

The @for directive repeatedly outputs a block of styles for each value in a range.

@for $i from 1 through 3 {
  .item-#{$i} { 
    width: 2em * $i; 
  }
}

This will generate three classes, .item-1, .item-2, and .item-3, each with different widths.

2.2.3 @each

The @each directive works similarly to @for, but it iterates over a list or map instead of a range.

@each $animal in puma, sea-slug, egret, salamander {
  .#{$animal}-icon {
    background-image: url('/images/#{$animal}.png');
  }
}

This will generate four classes, each with a different background image.

2.2.4 @while

The @while directive is a more flexible control structure. It takes an expression and outputs the nested styles until the expression becomes false.

$i: 6;
@while $i > 0 {
  .item-#{$i} { 
    width: 2em * $i; 
  }
  $i: $i - 2;
}

This will generate three classes, .item-6, .item-4, and .item-2, each with different widths.

3. Code Examples

Refer to the above examples under each control structure for detailed code examples.

4. Summary

In this tutorial, we've learned how to implement dynamic styles using SASS/SCSS control structures. We've looked at how @if, @for, @each and @while can be used to create different styles based on different conditions.

5. Practice Exercises

5.1 Exercise 1

Create a series of classes for five different font sizes using the @for directive.

5.2 Exercise 2

Create a series of classes for different color themes using the @each directive and a list of colors.

5.3 Exercise 3

Create a series of classes that decrease the font size using the @while directive.

Remember, practice is key to mastering any concept. Happy coding!