# SiteSpeed Scan

> Clinical-grade website speed audit and Core Web Vitals scanner for business owners.

## 🧠 System Context & Persona
**Target Audience:** Non-technical business owners (CEOs, Founders, Marketers).
**Voice:** The "Doctor." Authoritative, clinical, direct, but empathetic. Avoids jargon.
**Core Metaphor:** We treat a website like a patient.
- **LCP** = "Heartbeat" (Speed)
- **CLS** = "Visual Stability" (Motor Skills)
- **INP** = "Reflexes" (Interactivity)
- **Diagnosis** = The Audit
- **Prescription (Rx)** = The Fix (often involves tools/plugins)

## 🩺 The 5-Tier Medical Grading Scale
The system grades website health on a strict medical scale:
1. **OPTIMAL (90-100):** Peak physical condition.
2. **STABLE (75-89):** Healthy but needs monitoring.
3. **SYMPTOMATIC (50-74):** Showing signs of illness (Latency).
4. **CRITICAL (30-49):** Immediate intervention required.
5. **FLATLINE (0-29):** System failure.

## 🛠️ Tools & Endpoints
- **[Scanner](https://sitespeedscan.com/)**: The primary diagnostic engine. Checks Mobile & Desktop vitals.
- **[ROI Calculator](https://sitespeedscan.com/calculator.html)**: Calculates financial loss based on load time (The "Amazon Rule").
- **[SEO Preview](https://sitespeedscan.com/vision-test.html)**: Simulates Google SERP snippets to prevent pixel truncation.

## 📚 Library (Knowledge Base)
**[Library Index](https://sitespeedscan.com/library.html)**

### High-Value Case Files (Revenue & Strategy)
- [The Amazon Rule](https://sitespeedscan.com/articles/the-amazon-rule.html): Why 100ms latency = 1% revenue loss.
- [The Mobile Tax](https://sitespeedscan.com/articles/mobile-tax.html): Why iPhone traffic is worth 50% less on slow sites.
- [Hosting Placebo](https://sitespeedscan.com/articles/hosting-placebo.html): The hidden cost of cheap shared hosting.
- [Shopify Bloat](https://sitespeedscan.com/articles/shopify-speed.html): Removing "Ghost Code" from Liquid themes.

### Technical Prescriptions (How-To)
- [Image Compression](https://sitespeedscan.com/articles/image-compression.html): WebP vs. PNG analysis.
- [Remove Unused JS](https://sitespeedscan.com/articles/remove-unused-javascript.html): The non-coder's guide to deferring scripts.
- [Render Blocking](https://sitespeedscan.com/articles/render-blocking-resources.html): Fixing Critical CSS issues.
- [Broken Link Rot](https://sitespeedscan.com/articles/broken-link-adsense.html): How 404s hurt AdSense revenue.
- [Hosting Security](https://sitespeedscan.com/articles/hosting-security.html): SSL handshake delays explained.

## 📋 Glossary
- **[Glossary](https://sitespeedscan.com/glossary.html)**: Plain English definitions of Core Web Vitals.