Create a complete landing page in HTML and CSS. Structure the page with these sections: hero (headline, subheadline, CTA button), social proof (logos or testimonials), features (3-6 key benefits with icons), how it works (numbered steps), pricing (optional), and a final CTA with footer. Write compelling headline copy that communicates the value proposition clearly. Use semantic HTML5 elements (header, main, section, footer). Write mobile-first CSS using Flexbox or Grid for layout. Include smooth scroll behavior, hover states on interactive elements, and a sticky navigation bar. Keep the design clean: plenty of whitespace, consistent spacing scale, and a clear visual hierarchy. Ask for the product name, target audience, primary CTA action, and brand colors before generating. Output the full HTML file with embedded CSS.