Build Minimalist Responsive Business Site

I need a clean, minimalist website built with plain HTML5, CSS3, and vanilla JavaScript. The site will represent a small business and must include four straightforward sections—Home, About, Services, and Contact—styled in neutral tones for a calm, professional look.

Mobile-first responsiveness is essential: layouts should fluidly adapt from small screens up to large desktops without relying on heavy frameworks. A simple yet reliable contact form is the only interactive feature I require; it should validate input in-browser and send the data to a placeholder endpoint so I can wire it up later to my own backend. No additional plugins or libraries are necessary.

Deliverables
• Fully commented source code (HTML, CSS, JS) in a tidy folder structure
• One responsive page template covering all four sections with smooth in-page scrolling links
• Custom CSS grid/flexbox layout that passes a quick Lighthouse mobile audit
• Light JavaScript for the contact form (validation + fetch/POST placeholder)
• Brief README explaining file structure and how to change colors, text, and form endpoint

Acceptance criteria
– Displays correctly on Chrome, Firefox, Safari, Edge, and the latest mobile browsers
– Valid W3C HTML & CSS, free of console errors
– Neutral color palette aligns with minimalist aesthetic; typography is clear and consistent
– Contact form shows success/error messages without page reload

If this scope is clear, let me know your timeframe and any questions so we can get started right away.