1. Largest Contentful Paint
Featured images are preloaded on single articles and theme CSS keeps a safe fallback if CDN delivery is delayed.
RX Delivery Optimization
Core Web Vitals & Image Delivery
A calm technical checklist for keeping RX medical pages fast, stable, readable, and reachable for patients on mobile, weak internet, and CDN delivery.
2. Cumulative Layout Shift
Images and embeds receive safer loading attributes so text does not jump while patients are reading.
3. Interaction to Next Paint
Theme scripts remain lightweight so menus, RX Tools, and reading controls respond smoothly.
After every update, test these pages
- Homepage with normal design and mobile view.
- One long article with images, references, and article tools.
- RX Tools page and one guide page.
- Lite mode for weak internet.
- One page after CDN purge and one page after browser hard refresh.
| Layer | What to check | Good sign |
|---|---|---|
| Images | Featured image, article images, fallback images | No jumping, no broken image icon |
| CSS | CDN CSS plus local fallback | Design never appears as raw text |
| JavaScript | Menu, RX Tools dropdown, reading tools | Clicks respond quickly |
| CDN/cache | Purge after theme update | New version loads everywhere |
| Lite mode | ?rx_lite=1 and ?rx_full=1 | Weak internet reading remains available |
RX speed principle
Speed is not only a score. For RX Theme, speed means a worried patient can open the page, read the first useful guidance, and move toward proper care without delay.
