Svelte Guideline: Animation — Use tw-animate-css for entry/exit. Description: Ready-made animation classes imported in app.css. Do: class='animate-in fade-in slide-in-from-bottom-4 duration-300'. Don't: Manual CSS keyframes for standard entry animations. Good Example: <div class='animate-in fade-in duration-300'>. Bad Example: @keyframes fadeIn { from { opacity: 0 } }. Severity: Medium. Docs: .