Build a SaaS landing page

Build a complete, polished landing page for "Quill" — a SaaS tool that turns messy meeting notes into a clean list of action items. Include: a top nav with logo + links + a sign-up button, a hero (headline, subhead, primary CTA, and a simple product mockup), a three-feature section with icons, a short social-proof / logos strip, a pricing teaser, and a footer. Modern, confident visual design with a coherent type scale and spacing. Return one self-contained HTML file — all CSS in a <style> tag, no external frameworks, fonts, or image files. Output only the HTML.