Apply Transitions

Find parts of the UI that appear, disappear or change instantly, and give them transitions using the motion tokens in DESIGN.md.

Before you start

grep -A6 '^## Motion' DESIGN.md || echo "MISSING"

Stop if DESIGN.md has no Motion section. Adding durations without shared tokens creates the exact inconsistency this pass is meant to fix.

Step 1: Find changes with no transition

You're looking for something that's missing, so search for the places where UI changes, then check each one for a transition.

Things that show and hide:

# Svelte
grep -rn '{#if' src --include="*.svelte" | head -40
# React and JSX
grep -rn -E '\{\s*\w+\s*&&\s*<|\{\s*\w+\s*\?\s*<' src --include="*.tsx" --include="*.jsx" | head -40
# Vue
grep -rn 'v-if=' src --include="*.vue" | head -40

For each result, check whether the element has transition:, <AnimatePresence> or <Transition>. Note the ones that don't. The usual suspects are modals, dropdowns, toasts, tooltips, accordions, tab panels, error messages and loading states.

Hover, focus and open states:

grep -rn -E 'hover:|focus:|active:|aria-expanded|data-state' src --include="*.svelte" --include="*.tsx" | grep -v 'transition' | head -40

For example, a hover:bg-* without transition-colors changes color instantly.

Inline styles that change:

grep -rn -E 'style=.*(height|width|opacity|transform).*\$?\{' src --include="*.svelte" --include="*.tsx" | head -20

Step 2: Pick a speed by the kind of interaction

Choose the duration by what kind of interaction it is, not element by element.

Kind	Duration	Examples
Small	150ms	hover, focus, press, checkbox, toggle
Standard	250ms	dropdown, tooltip, popover, accordion, tab
Large	400ms	modal, drawer, page change, anything full-screen

Use the duration tokens from the Motion section of DESIGN.md, not raw numbers. Take the easing from there too: the ease-out curve for things entering, ease-in for things leaving.

Step 3: Rules for every transition

Only animate transform and opacity. Animating width, height, top or margin makes the browser redo the page layout on every frame, which stutters. To animate height, animate grid-template-rows or use a scale transform instead.

Respect the reduced-motion setting. Add this whenever you add transitions:

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

With reduced motion on, keep fades and remove movement. Sliding and zooming can make people with motion sensitivity feel sick. Fades don't.

Don't animate things that are already there when the page loads. Animate elements when they appear or change, not on first render.

Step 4: Report

For each file: what you found, which kind of interaction it is, and the token you used. Then the total for each kind.

List anything you deliberately left without a transition, and why. Some changes should be instant.