index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>light and dark mode</title>
    <link rel="stylesheet" href="style.css">
    <link href='https://unpkg.com/boxicons@2.1.4/css/boxicons.min.css' rel='stylesheet'>
</head>
<body>
    
    <div class="light-mode">
        <header class="header">
            <h2 class="mode-title">
                Light mode
            </h2>
            <i class='bx bxs-sun' onclick="toggle('dark')"></i>
        </header>
        <div class="show-case">
            <img src="images/light.jpg" alt="" class="image">
            <p class="description">
                In the light, I can be your snow white.
            </p>
        </div>
    </div>

    <div class="dark-mode">
        <header class="header">
            <h2 class="mode-title">
                Dark mode
            </h2>
            <i class='bx bxs-moon' onclick="toggle('light')"></i>
        </header>
        <div class="show-case">
            <img src="images/dark.jpg" alt="" class="image">
            <p class="description">
                On the night, I will be your dark knight.
            </p>
        </div>
    </div>

    <script src="script.js"></script>
</body>
</html>