Html Css Javascript Crash Course -

.demo-box background: var(--box-bg); border: 1px solid var(--box-border); border-radius: 12px; padding: 1.5rem; margin: 2rem 0; transition: 0.2s;

// Update button text & save preference if (body.classList.contains('dark')) button.textContent = '☀️ Light Mode'; localStorage.setItem('theme', 'dark'); else button.textContent = '🌙 Dark Mode'; localStorage.setItem('theme', 'light'); html css javascript crash course

// Toggle theme on button click button.addEventListener('click', () => body.classList.toggle('dark'); .demo-box background: var(--box-bg)

JavaScript adds logic and user interaction. border: 1px solid var(--box-border)