<button id="darkModeToggle">Toggle Dark/Light Mode</button>
<div class="content-area">
  <h2>Sample Heading</h2>
  <p>This is some sample content that will change its appearance based on the selected theme. Try toggling the mode!</p>
</div>

:root {
  --bg-color: #ffffff;
  --text-color: #333333;
  --content-bg: #f4f4f4;
  --button-bg: #e0e0e0;
  --button-text: #333333;
}

[data-theme="dark"] {
  --bg-color: #333333;
  --text-color: #ffffff;
  --content-bg: #444444;
  --button-bg: #555555;
  --button-text: #ffffff;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: sans-serif;
  transition: background-color 0.3s, color 0.3s;
  padding: 20px;
}

.content-area {
  background-color: var(--content-bg);
  padding: 20px;
  margin-top: 20px;
  border-radius: 5px;
  transition: background-color 0.3s;
}

#darkModeToggle {
  padding: 10px 15px;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: 1px solid var(--text-color);
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.3s, color 0.3s;
}

const toggleButton = document.getElementById('darkModeToggle');
const currentTheme = localStorage.getItem('theme');

if (currentTheme) {
    document.documentElement.setAttribute('data-theme', currentTheme);
}

toggleButton.addEventListener('click', () => {
    let theme = document.documentElement.getAttribute('data-theme');
    if (theme === 'dark') {
        document.documentElement.removeAttribute('data-theme');
        localStorage.removeItem('theme');
    } else {
        document.documentElement.setAttribute('data-theme', 'dark');
        localStorage.setItem('theme', 'dark');
    }
});