Multiple Themes using JS and CSS

This time we are going to create multiple themes switch similar to this Multiple themes with JS and JSON but much easier. So let's get to work.
First we need our HTML structure

<div class="themes">
    <div class="theme" onclick="changeTheme('light')"></div>
    <div class="theme" onclick="changeTheme('dark')"></div>
    <div class="theme" onclick="changeTheme('red')"></div>
</div>
<div class="container">
        <div class="container">
            <h2>Themes Switcher Using CSS Classes</h2>
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        </div>

We have our HTML, now it's time for CSS

* {
  margin: 0;
  padding: 0;
  font-family: 'Poppins', sans-serif;
  box-sizing: border-box;
}
body {
  background-color: var(--bg-color);
  color: var(--text);
}
h1 {
  margin-top: 20px;
  margin-left: 1rem;
}
.themes {
  display: flex;
  justify-content: space-around;
  align-items: center;
  border-radius: 8px;
  padding: 20px;
  width: 200px;
  background-color: var(--secondary);
  margin-left: 1rem;
  margin-top: 20px;
}
.themes .theme {
  width: 30px;
  border-radius: 8px;
  height: 30px;
  cursor: pointer;
}
.themes .theme:nth-child(1) {
  background-color: #ddd;
}
.themes .theme:nth-child(2) {
  background-color: #333;
}
.themes .theme:nth-child(3) {
  background-color: rgb(57, 2, 2);
}

.container {
  width: min(100% - 2rem, 1200px);
  margin-top: 80px;
  margin-inline: auto;
  background-color: var(--secondary);
  padding: 20px;
}

Ok, we have CSS structure, we can add default, dark and red theme now

:root {
  --bg-color: #eee;
  --secondary: #ccc;
  --text: #333;
}
.dark {
  --bg-color: #333;
  --secondary: #222;
  --text: #ddd;
}
.red {
  --bg-color: rgb(57, 2, 2);
  --secondary: rgb(102, 23, 23);
  --text: rgb(235, 235, 235);
}

Our Page looks like this now

But we can't change our themes without JavaScript

const changeTheme = (theme) => {
    document.body.classList = ''
    document.body.classList.add(theme)
}

That's better.
Here is the result:
Light(default) theme:

Dark theme:

Red theme:

But we're not finished yet. As in my previous post, we will to add localStorage.
First we need to find matching theme and then set localStorage

switch (theme) {
    case 'light':
        localStorage.setItem('theme', 'light')
        break
    case 'dark':
        localStorage.setItem('theme', 'dark')
        break
    case 'blue':
        localStorage.setItem('theme', 'blue')
        break
}

And let's load localStorage

document.body.classList = localStorage.getItem('theme')

For all files visit my Github Respository.

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