ROI app for your mobile device
Here’s a 100% mobile-optimized, installable web app version of your 9x12 Shared Postcard ROI Calculator that works and feels like a native app on any phone (iPhone or Android). Just save the code below as a single file named index.html, upload it to your website (or even host it for free on Netlify/Vercel), and share the link with your reps or advertisers. When someone opens the link on their phone, they’ll get a prompt to “Add to Home Screen” → it will install as a full-screen app with your icon and name. <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" /> <title>9x12 Postcard ROI</title> <!-- Make it installable (PWA) --> <link rel="manifest" href="data:application/manifest+json,{ \"name\": \"9x12 Postcard ROI Calculator\", \"short_name\": \"Postcard ROI\", \"start_url\": \".\", \"display\": \"standalone\", \"background_color\": \"#ffffff\", \"theme_color\": \"#28a745\", \"icons\": [ {\"src\":\"https://americanspotlights.com/favicon-192.png\",\"sizes\":\"192x192\",\"type\":\"image/png\"}, {\"src\":\"https://americanspotlights.com/favicon-512.png\",\"sizes\":\"512x512\",\"type\":\"image/png\"} ] }" /> <link rel="apple-touch-icon" href="https://americanspotlights.com/favicon-192.png" /> <style> body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; margin:0; background:#f4f4f4; padding:env(safe-area-inset); } .container { max-width:500px; margin:0 auto; background:white; min-height:100vh; } header { background:#28a745; color:white; text-align:center; padding:20px 15px; font-size:24px; font-weight:bold; }