make-interfaces-feel-better

# Details that make interfaces feel better Great interfaces rarely come from a single thing. It's usually a collection of small details that compound into a great experience. Apply these principles when building or reviewing UI code. ## Quick Reference | Category | When to Read | | --- | --- | | [Typography](references/typography.md) | Text wrapping, font smoothing, tabular numbers | | [Surfaces](references/surfaces.md) | Border radius, optical alignment, shadows, image outlines, hit areas | | [Animations](references/animations.md) | Interruptible animations, enter/exit transitions, icon animations, scale on press | | [Performance](references/performance.md) | Transition specificity, `will-change` usage | ## Core Principles ### 1. Concentric Border Radius Outer radius = inner radius + padding. Mismatched radii on nested elements is the most common thing that makes interfaces feel off. ### 2. Optical Over Geometric Alignment When geometric centering looks off, align optically. Buttons with icons, play triangles, and asymmetric icons all need manual adjustment. ### 3. Shadows Over Borders Layer multiple transparent `box-shadow` values for natural depth. Shadows adapt to any background; solid borders don't. ### 4. Interruptible Animations Use CSS transitions for interactive state changes — they can be interrupted mid-animation. Reserve keyframes for staged sequences that run once. ### 5. Split and Stagger Enter Animations Don't animate a single container. Break content into semantic chunks and stagger each with ~100ms delay. ### 6. Subtle Exit Animations Use a small fixed `translateY` instead of full height. Exits should be softer than enters. ### 7. Contextual Icon Animations Animate icons with `opacity`, `scale`, and `blur` instead of toggling visibility. Use exactly these values: scale from `0.25` to `1`, opacity from `0` to `1`, blur from `4px` to `0px`. If the project has `motion` or `framer-motion` in `package.json`, use `transition: { type: "spring", duration: 0.3, bounce: 0 }` — bounce must always be `0`. If no motion library is installed, keep both icons in the DOM (one absolute-positioned) and cross-fade with CSS transitions using `cubic-bezier(0.2, 0, 0, 1)` — this gives both enter and exit animations without any dependency. ### 8. Font Smoothing Apply `-webkit-font-smoothing: antialiased` to the root layout on macOS for crisper text. ### 9. Tabular Numbers Use `font-variant-numeric: tabular-nums` for any dynamically updating numbers to prevent layout shift. ### 10. Text Wrapping Use `text-wrap: balance` on headings. Use `text-wrap: pretty` for body text to avoid orphans. ### 11. Image Outlines Add a subtle `1px` outline with low opacity to images for consistent depth. ### 12. Scale on Press A subtle `scale(0.96)` on click gives buttons tactile feedback. Always use `0.96`. Never use a value smaller than `0.95` — anything below feels exaggerated. Add a `static` prop to disable it when motion would be distracting. ### 13. Skip Animation on Page Load Use `initial={false}` on `AnimatePresence` to prevent enter animations on first render. Verify it doesn't break intentional entrance animations. ### 14. Never Use `transition: all` Always specify exact properties: `transition-property: scale, opacity`. Tailwind's `transition-transform` covers `transform, translate, scale, rotate`. ### 15. Use `will-change` Sparingly Only for `transform`, `opacity`, `filter` — properties the GPU can composite. Never use `will-change: all`. Only add when you notice first-frame stutter. ### 16. Minimum Hit Area Interactive elements need at least 40×40px hit area. Extend with a pseudo-element if the visible element is smaller. Never let hit areas of two elements overlap. ## Common Mistakes | Mistake | Fix | | --- | --- | | Same border radius on parent and child | Calculate `outerRadius = innerRadius + padding` | | Icons look off-center | Adjust optically with padding or fix SVG directly | | Hard borders between sections | Use layered `box-shadow` with transparency | | Jarring enter/exit animations | Split, stagger, and keep exits subtle | | Numbers cause layout shift | Apply `tabular-nums` | | Heavy text on macOS | Apply `antialiased` to root | | Animation plays on page load | Add `initial={false}` to `AnimatePresence` | | `transition: all` on elements | Specify exact properties | | First-frame animation stutter | Add `will-change: transform` (sparingly) | | Tiny hit areas on small controls | Extend with pseudo-element to 40×40px | ## Review Checklist - [ ] Nested rounded elements use concentric border radius - [ ] Icons are optically centered, not just geometrically - [ ] Shadows used instead of borders where appropriate - [ ] Enter animations are split and staggered - [ ] Exit animations are subtle - [ ] Dynamic numbers use tabular-nums - [ ] Font smoothing is applied - [ ] Headings use text-wrap: balance - [ ] Images have subtle outlines - [ ] Buttons use scale on press where appropriate - [ ] AnimatePresence uses `initial={false}` for default-state elements - [ ] No `transition: all` — only specific properties - [ ] `will-change` only on transform/opacity/filter, never `all` - [ ] Interactive elements have at least 40×40px hit area