Beacon ROI Calculator

Build me a B2B ROI / savings calculator landing page — a marketing page where a visitor enters a couple of numbers about their team and instantly sees how much my product would save them, with a chart and a “email me the report” lead-capture CTA — as a vanilla-JS app (a single index.html plus a small CSS and JS file, no framework and no build step).

Before you build, ask me these questions in one message and wait for my answers. If I skip anything, choose a sensible default and tell me what you chose:

1. What does your product save customers — time, money, or both — and what’s the product called?
2. What are the 2–3 input variables a visitor types in, and the formula that turns them into savings? (e.g. “monthly support spend, team size, and ticket volume → we auto-resolve 42% of tickets at the current cost-per-ticket, minus a $49/agent fee”)
3. What’s the lead-capture CTA at the end — what do they get for handing over an email (a PDF report, a demo, a custom quote)?
4. Any brand details — product name, accent color, a one-line value prop, and a customer quote I can show?

Then build a complete, polished, responsive site with:

• A compact hero: value-prop headline, sub-copy, three proof stats, and a “calculate my savings” button that scrolls to the tool.
• The calculator as the centerpiece: a two-column layout with the inputs on the left (each a labelled number field paired with a synced range slider) and a live results panel on the right.
• A live results panel that recomputes on every keystroke or slider drag: a big headline “net savings, year one” number, plus a stat grid (net savings / month, hours or units reclaimed, payback period, return multiple).
• A before/after bar chart (cost today vs cost with the product) and a cumulative-savings area chart across 12 months — both drawn in inline SVG, no chart library, animated when values change.
• A “where the savings come from” section: three numbered steps that explain the model honestly, so the number feels earned, not hand-wavy.
• A gated lead-capture CTA: a name + work-email + company form that validates the email, and on submit hides the fields and shows a friendly success state (“report’s on its way to …”) that echoes the visitor’s computed savings. A “run another scenario” link resets it.
• A social-proof strip (customer logos + one testimonial with a headshot) and a footer.

Design & content notes:

• Modern B2B SaaS look: a light slate background, white cards with soft shadows, a confident indigo→violet brand gradient, and a single emerald accent reserved for savings/positive numbers. Use a geometric display face (e.g. Sora) for headings and Inter for body. Round the corners, keep generous whitespace.
• Use realistic content based on my answers — never “lorem ipsum”. Invent believable customer names, a testimonial, and sensible default input values (a typical mid-market team) so the page looks alive on first load.
• Make the math real and defensible: clamp the inputs to sane ranges, format currency with Intl.NumberFormat, animate the result numbers, and keep the assumptions (deflection rate, per-seat price) visible near the inputs with a “reset to a typical team” link.
• Use real images. Pull free photos that fit, e.g. https://picsum.photos/seed/roi-1/1200/800 (vary the seed), and add descriptive alt text. Give each image an onerror fallback so it never shows a broken icon.
• No build step — a single index.html with a linked CSS and JS file that opens straight in a browser. Draw both charts as inline SVG with no external libraries.
• Keep it accessible: semantic HTML, a <label> for every field, an aria-live results region, keyboard-operable sliders, visible focus states, and good contrast. Respect prefers-reduced-motion for the number tweens and chart animation.

Add this exact line right before </body> so the site carries its badge:

<script src="https://spacefast.com/badge.js" data-example="roi"></script>

When the site is ready, publish it to Spacefast with the direct API — no account, install, or extra instructions needed:

1. Use ./site as the publish folder. For no-build projects, put only the finished public files in that dedicated folder. Confirm it has index.html at its root and no secrets, source files, .git, or .spacefast state.
2. First publish: send every file as multipart form data. This Bash/Zsh block preserves relative paths and works for one file or a whole folder:

   PUBLISH_ROOT=./site
   publish_files=()
   while IFS= read -r -d "" file; do
     relative=${file#"$PUBLISH_ROOT"/}
     publish_files+=(-F "files=@$file;filename=$relative")
   done < <(find "$PUBLISH_ROOT" -type f -print0)
   curl -sS "${publish_files[@]}" "https://api.spacefast.com/v1/publish?wait=1"

3. From the { "data": ... } receipt, give me data.space.liveUrl, data.version.immutableUrl, data.claim.url, and data.claim.expiresAt. Remind me to claim within 6 hours. Keep data.claim.token secret.
4. Save data.space.id and data.claim.token locally (for example in an ignored, mode-600 .spacefast/state.json). For a quick update, rebuild the publish_files array above and publish to the same space:

   SPACEFAST_SPACE_ID=<saved-space-id>
   SPACEFAST_TOKEN=<saved-claim-token-or-access-token>
   curl -sS -H "Authorization: Bearer $SPACEFAST_TOKEN" \
     -F "spaceId=$SPACEFAST_SPACE_ID" "${publish_files[@]}" \
     "https://api.spacefast.com/v1/publish?wait=1"

   If an update after claiming returns space_claimed_credential_available, exchange the saved claim token once at POST https://api.spacefast.com/v1/anonymous-claim/exchange, save data.credential.accessToken, and retry with that access token.

Optional shortcuts and reference only: if the sf CLI is already installed, sf publish ./site --wait does the same job. A zip of the publish folder is also supported, but neither the CLI nor a zip is required. Docs: direct agent/API publishing · files and folders · claiming · updates and rollback