# Details that make interfaces feel better Great interfaces rarely come from a single thing. It is usually a collection of small details that compound into a great experience. Before changing anything, detect the project's existing styling and motion systems and express the fix in those systems. Never introduce a second styling system for a polish pass. For motion work, inspect the interface at 10% speed in browser animation tooling and walk default, hover, focus-visible, active, loading, empty, disabled, and reduced-motion states. A full-speed happy-path replay is not sufficient proof. ## Quick Reference | Category | When to Use | | --- | --- | | [Typography](typography.md) | Text wrapping, font smoothing, tabular numbers | | [Surfaces](surfaces.md) | Border radius, optical alignment, shadows, image outlines, hit areas | | [Animations](animations.md) | Interruptible animations, enter/exit transitions, icon animations, scale on press | | [Icons](icons.md) | Optical weight, one SVG across states, render-size checks, RTL behavior | | [Performance](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 for Elevation, Borders for Structure Use layered transparent shadows for elevation. Keep borders when they communicate structure or state: dividers, layout boundaries, selection, and focus. ### 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 For infrequent staged entrances where sequence clarifies hierarchy, split semantic chunks and stagger by about 100ms. Do not stagger routine, high-frequency interactions. ### 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. Use untinted black in light mode and untinted white in dark mode unless the brand system explicitly requires another neutral; colored outlines make media feel muddy. ### 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 44×44px hit area on touch/mobile surfaces and at least 40×40px on precise-pointer desktop surfaces. Extend with a pseudo-element if the visible element is smaller. Never let hit areas of two elements overlap. ### 17. Visible State Matrix For compact controls, verify every interactive state: default, hover, pressed, active/selected, focus-visible, disabled, and loading. The visible glyph can stay small, but the active state and hit target must be obvious in screenshots and browser inspection. ### 18. Motion Restraint Do not add custom animation to high-frequency interactions. Motion must never be the only feedback channel; pair it with a static change such as color, icon, label, or position, and provide a reduced-motion result. ## 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 44×44px on touch or 40×40px on desktop | | Compact control state is ambiguous | Show default, hover, pressed, active, focus, disabled, and loading states | ## 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 44×44px touch or 40×40px desktop hit area - [ ] Compact controls show default/hover/pressed/active/focus/disabled/loading states ## Reference Files - [typography.md](typography.md) — Text wrapping, font smoothing, tabular numbers - [surfaces.md](surfaces.md) — Border radius, optical alignment, shadows, image outlines - [animations.md](animations.md) — Interruptible animations, enter/exit transitions, icon animations, scale on press - [performance.md](performance.md) — Transition specificity, `will-change` usage ## Folded Skill References These former standalone skills are bundled here as references to keep the runtime list compact. Load only the reference that matches the user's exact product, framework, or failure mode. | Former skill | Reference | Description | | --- | --- | --- | | `dedalus-make-interfaces-feel-better` | [`references/skills/dedalus-make-interfaces-feel-better/SKILL.md`](references/skills/dedalus-make-interfaces-feel-better/SKILL.md) | Design engineering principles for making interfaces feel polished. Use when building UI components, reviewing frontend code, implementing animations, hover states, shadows, borders, typography, micro-interactions, enter/exit animations, or any visual detail work. Triggers on UI polish, design details, "make it feel better", "feels off", stagger animations, border radius, optical alignment, font smoothing, tabular numbers, image outlines, box shadows. |