ui-ux-design-best-practices

name

ui-ux-design-best-practices

description

UI/UX polish, component design, animation decisions, and Tailwind v4 patterns for making interfaces feel right. Use when reviewing, writing, or refactoring UI code involving animations, transitions, CSS transforms, gestures, Tailwind utility classes, or interactive component behavior. Triggers on tasks involving motion design, interactive states (hover/active/focus), component feel, or any use of Tailwind transition/transform/animation utilities.

UI/UX Design Best Practices

Guidelines for building interfaces where every interaction detail compounds into something that feels right. Covers animation decisions, Tailwind v4 motion utilities, component interaction patterns, and accessibility requirements.

When to Apply

Load this skill when:

• Writing or reviewing components with hover, active, focus, or enter/exit animations
• Implementing transitions, transforms, or keyframe animations (CSS or Tailwind)
• Reviewing Tailwind utility usage for motion-related classes
• Designing interactive elements: buttons, dropdowns, modals, drawers, tooltips, popovers
• Checking accessibility for motion sensitivity (prefers-reduced-motion)
• Implementing gesture or drag interactions
• Debugging janky or sluggish animations

Reference Documentation

Animation

• rules/animation-decision-framework.md - core philosophy, should-animate decision tree, easing selection, duration cheatsheet, perceived performance
• rules/animation-springs.md - spring config (Framer Motion / Motion), mouse interactions, interruptibility advantage
• rules/animation-component-patterns.md - buttons, scale(0) rule, origin-aware popovers, tooltip instant-on-subsequent, blur crossfades
• rules/animation-transitions-transforms.md - CSS transitions vs keyframes, @starting-style, translateY percentages, scale children, GPU acceleration
• rules/animation-clip-path.md - inset() shape, hold-to-delete/confirm pattern, tab color transitions, scroll reveals, comparison sliders
• rules/animation-gestures.md - momentum dismissal, boundary damping, pointer capture, multi-touch protection, friction stops
• rules/animation-performance.md - only animate transform/opacity, CSS variable inheritance, Framer Motion hardware acceleration, WAAPI
• rules/animation-accessibility-stagger.md - prefers-reduced-motion, touch hover gating, stagger delays, asymmetric enter/exit timing
• rules/animation-review-checklist.md - component design principles, slow-motion debugging, review checklist table

Tailwind v4

• rules/tailwind-v4-changes.md - v3→v4 migration table, arbitrary value syntax, CSS variable shorthand
• rules/tailwind-transitions.md - transition-property, transition-duration, transition-timing-function, transition-delay
• rules/tailwind-transforms.md - scale, translate, rotate, transform-origin, GPU transform-gpu
• rules/tailwind-animations.md - animate-* builtins, custom @theme keyframes
• rules/tailwind-effects.md - opacity, blur, backdrop-blur
• rules/tailwind-interactivity.md - will-change, pointer-events, cursor, user-select
• rules/tailwind-variants.md - motion-reduce: / motion-safe:, touch hover gating, starting:, stacking variants
• rules/tailwind-patterns.md - ready-to-use patterns (button, dropdown, modal, toast, tooltip, stagger, frosted glass) + anti-patterns table

Quick Reference

The One Rule

Only animate transform and opacity. These skip layout and paint, running on the GPU. Animating height, padding, margin, or width triggers all three rendering steps and causes jank.

Animation Decision by Frequency

Frequency	Decision
100+ times/day (keyboard shortcuts, command palette)	No animation - ever
Tens of times/day (hover effects, list navigation)	Remove or drastically reduce
Occasional (modals, drawers, toasts)	Standard animation
Rare or first-time (onboarding, celebrations)	Can add delight

Duration Cheatsheet

Element	Duration
Button press feedback	100–160ms
Tooltips, small popovers	125–200ms
Dropdowns, selects	150–250ms
Modals, drawers	200–500ms
Marketing / explanatory	Can be longer

Rule: UI animations under 300ms. A 180ms dropdown feels more responsive than a 400ms one.

Easing Cheatsheet

Situation	Easing	Tailwind
Element entering / exiting	ease-out	ease-out
Element moving on screen	ease-in-out	ease-in-out
Hover / color change	ease	ease-linear or default
Constant motion (spinner, marquee)	linear	ease-linear

Never use ease-in for UI interactions. It starts slow - the exact moment the user is watching most closely - making the interface feel sluggish.

Custom Easing Values (register in @theme)

@theme {
  --ease-out-strong:  cubic-bezier(0.23, 1, 0.32, 1);
  --ease-in-out-strong: cubic-bezier(0.77, 0, 0.175, 1);
  --ease-drawer: cubic-bezier(0.32, 0.72, 0, 1);
}

<!-- Use in Tailwind via CSS variable shorthand -->
<div class="ease-(--ease-out-strong)">...</div>

Tailwind Quick Patterns

<!-- Button press feedback -->
<button class="transition-transform duration-160 ease-out active:scale-[0.97]">

<!-- Dropdown / popover entry (scale from origin) -->
<div class="transition-[transform,opacity] duration-200 ease-out
            data-[state=closed]:scale-95 data-[state=closed]:opacity-0
            origin-top-left">

<!-- Toast / modal entry -->
<div class="transition-[transform,opacity] duration-300 ease-out
            starting:opacity-0 starting:translate-y-4">

<!-- Respect reduced motion -->
<div class="transition-transform motion-reduce:transition-none">

Review Format

When reviewing UI code, output a markdown table:

Before	After	Why
transition: all 300ms	transition: transform 200ms ease-out	Specify exact properties; avoid all
transform: scale(0)	transform: scale(0.95); opacity: 0	Nothing appears from nothing
ease-in on dropdown	ease-out with custom curve	ease-in feels sluggish
No :active state on button	active:scale-[0.97]	Buttons must feel responsive to press
transform-origin: center on popover	origin-[var(--radix-popover-content-transform-origin)]	Scale from trigger, not center
Animation on keyboard action	Remove animation entirely	Repeated 100x/day - animation adds delay
Duration > 300ms on UI element	Reduce to 150–250ms	Slow transitions feel broken
Hover without @media (hover: hover) guard	Add @media (hover: hover) and (pointer: fine)	Touch devices trigger hover on tap
Keyframes on rapidly-triggered element	CSS transitions for interruptibility	Keyframes restart from zero on interruption
Framer Motion x/y props under load	transform: "translateX()" string	Short-hand props are not hardware-accelerated
Same enter/exit speed	Exit faster than enter	Slow deliberate entry, snappy exit
All elements appear at once	Stagger 30–80ms between items	Cascading feels more natural

Full Reference

For detailed explanations, code examples, and Tailwind mappings, read the files listed in Reference Documentation above. Load only the specific rule files relevant to the current task to minimize token usage.