CSSmarkup~30 mins

Theme implementation basics in CSS - Mini Project: Build & Apply

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Theme Implementation Basics with CSS Variables

📖 Scenario: You are building a simple webpage that can switch between a light theme and a dark theme. To do this, you will use CSS custom properties (variables) to define colors for the themes.

🎯 Goal: Create CSS variables for colors, set up a light theme as default, add a dark theme configuration, and apply the dark theme using a CSS class.

📋 What You'll Learn

Use CSS custom properties to define colors

Create a :root selector with light theme colors

Create a .dark-theme class with dark theme colors

Apply the dark theme by adding the .dark-theme class to the body element

💡 Why This Matters

🌍 Real World

Many websites offer light and dark themes to improve user comfort and accessibility. Using CSS variables makes switching themes easy and maintainable.

💼 Career

Understanding CSS variables and theme implementation is important for front-end developers to create modern, user-friendly websites.

Progress0 / 4 steps

Define light theme colors using CSS variables

Create a :root selector and define these CSS variables: --background-color with value #ffffff, --text-color with value #000000.

CSS

:root {
  /* Define light theme colors here */
}

Need a hint?

Use the :root selector to define CSS variables for the light theme colors.

Create a dark theme class with CSS variables

Add a CSS class called .dark-theme that defines the CSS variables --background-color with value #121212 and --text-color with value #e0e0e0.

CSS

:root {
  --background-color: #ffffff;
  --text-color: #000000;
}

.dark-theme {
  /* Define dark theme colors here */
}

Need a hint?

Use the .dark-theme class to override the CSS variables with dark theme colors.

Apply CSS variables to the body element

Write CSS rules for the body element to use the CSS variables --background-color for background-color and --text-color for color.

CSS

:root {
  --background-color: #ffffff;
  --text-color: #000000;
}

.dark-theme {
  --background-color: #121212;
  --text-color: #e0e0e0;
}

body {
  /* Use CSS variables for colors here */
}

Need a hint?

Use the var() function to apply CSS variables to the body element's styles.

Add the dark theme class to the body element

Add the class dark-theme to the body element in your HTML to apply the dark theme colors.

CSS

Need a hint?

In your HTML, add class="dark-theme" inside the <body> tag.