What is Offline Fallback & App Shell?
A cached shell that renders when the network fails. Offline capability is a reliability feature users notice exactly when they need it most.
Related terms
Service Worker
The background script owning cache and update lifecycle. Versioned caches with explicit update prompts beat silent staleness every time.
PWA Manifest & Icons
The metadata making a site installable: name, icons, theme color, display mode. Manifest plus service worker turns a website into an app-like install.
Safe-Area Layout
Respecting notches, home indicators, and dynamic viewport units on mobile. Safe-area insets and dvh units keep CTAs tappable on every device.
Svelte Runes
The `$state`, `$derived`, `$effect`, and `$props` primitives powering Svelte 5 reactivity. Runes are mandatory in generated code: explicit, compilable, and consistent across every component.
File-Based Routing
Pages defined by file location: `+page.svelte` renders, `+layout.svelte` wraps, `+server.js` serves data. The route tree is the app map — no separate router config to drift.
Load Function
Server-side data loading for a route before it renders. Load on the server for content crawlers and users need immediately; reach for client fetching only for interactive extras.