Build a Responsive Navigation with Mobile Menu

Create a responsive top navigation bar for this app. On desktop (768px and wider), show the logo on the left, four navigation links centered (Features, Pricing, Docs, Blog), and a CTA button ("Get started") on the right. On mobile, hide the nav links and replace them with a hamburger icon button on the right side of the nav. When tapped, the hamburger should toggle a full-width dropdown panel below the nav bar showing the same four links stacked vertically with adequate tap target size, plus the CTA button at the bottom. The nav should have a subtle 1px border-bottom and become sticky when the user scrolls past the top of the page. Highlight the currently active page link with a different color or underline. Close the mobile menu automatically when the user clicks any link, clicks anywhere outside the dropdown, or presses the Escape key.