Use this skill when the user wants to make their app look better, says it looks like a template, asks how to achieve Stripe/Linear quality, or says something looks off. Covers visual hierarchy, whitespace, composition, color application, and typography in practice.
Make web apps look intentionally designed rather than AI-generated. This skill covers the visual principles that separate premium-feeling apps (Stripe, Linear, Vercel) from generic template output. Apply these principles when building new UI or when the user says something "looks off" but can't articulate why.
Reference AI-SLOP-FIXES.md for specific antipattern remediation. Reference REFERENCE-TEARDOWNS.md for concrete examples from production apps.
This is the single most impactful skill. A clear hierarchy makes any design feel professional; a muddled one makes even beautiful components feel amateurish.
Size difference. The primary element should be dramatically larger than secondary elements. Not 10% larger — 50-100% larger. A page heading at text-3xl with body at text-sm creates immediate hierarchy. A heading at text-xl with body at text-lg creates mush.
Weight contrast. Pair font-bold (700) headings with font-normal (400) body text. Never use font-medium (500) for both headings and body — the difference is invisible. Use at most 3 font weights per page: one for headings, one for body, one for de-emphasized text.
Color contrast. Primary content in text-gray-900, secondary in text-gray-500, tertiary in text-gray-400. Three levels is usually enough. Don't use text-gray-700 and text-gray-600 on the same page — the difference is imperceptible.
Spatial hierarchy. The most important element gets the most surrounding whitespace. A CTA button with py-3 px-8 surrounded by mt-8 commands more attention than one with py-2 px-4 and mt-4.
text-base font-medium text-gray-700. Fix: Pick ONE weight/size for body, make headings dramatically different.text-sm font-normal text-gray-500 for nav items.bg-primary text-white button per section. Everything else is text-gray-600 hover:text-gray-900 or a ghost/outline variant.If items inside a card are spaced with gap-3 (12px), the gap between cards should be gap-6 (24px) or more. If sections use gap-6 internally, section gaps should be py-16 or py-20. This ratio (2-3x) is the single most important spacing principle.
px-6 minimum on mobile, px-8 to px-12 on desktop. Cramped edges make everything feel cheap.pt-8 to pt-12 before the first heading. Content that starts immediately below the nav feels rushed.py-12 to py-20 between major sections. This is almost always too small in AI-generated output.mt-6 to mt-8 above a CTA gives it importance.p-6 is the minimum for cards with content. p-4 works for compact list items but feels cramped for standalone cards.py-2 to py-3) with compact cells are fine — density is the point.py-2 px-3 keeps nav compact and functional.gap-4 to gap-5 between form fields is appropriate — too much space makes forms feel disconnected.gap-1.5 to gap-2. Badge padding of px-2 py-0.5.Most AI-generated apps flip this ratio — too much accent color, not enough neutral space. If more than 10% of the visible pixels are your brand color, pull back.
bg-blue-50 not bg-blue-500.bg-green-50, bg-red-50) with full saturation for text and icons (text-green-700, text-red-700).bg-blue-600 hero section screams template. Use bg-white or bg-gray-50 with a blue accent element instead.Use exactly two weights for most UI: font-semibold (600) for headings and labels, font-normal (400) for body and descriptions. Add font-medium (500) only if you genuinely need a third level (e.g., subheadings within a section). Never use font-light (300) — it's unreadable at small sizes on most screens.
Maintain a clear step ratio between sizes. A practical scale:
| Role | Tailwind | Size |
|---|---|---|
| Page title | text-2xl or text-3xl | 24-30px |
| Section heading | text-xl | 20px |
| Card title | text-lg or text-base font-semibold | 16-18px |
| Body | text-sm or text-base | 14-16px |
| Secondary/meta | text-xs or text-sm | 12-14px |
The key: adjacent levels in the hierarchy should be at least 2 Tailwind size steps apart. text-base heading with text-sm body works. text-lg heading with text-base body is too close.
Body text should never exceed max-w-prose (~65ch). Text that stretches across a full-width container is the fastest way to look unprofessional. For headings, max-w-2xl keeps them from stretching too wide on large screens.
text-3xl and up): add tracking-tight (-0.025em). Large text has too much natural spacing.tracking-wide or tracking-wider. Uppercase text without extra tracking looks cramped.Pick ONE alignment edge for content and stick to it across pages. Left-align is correct for 90% of SaaS UIs. Center-align only for: hero sections, empty states, and confirmation dialogs. Never center body text, form fields, or data.
Repeating elements (cards, list items, table rows) must be identical in structure. Same padding, same text sizes, same spacing between elements within each item. Variation in repeating elements creates visual noise — the eye constantly readjusts instead of scanning smoothly.
max-w-lg to max-w-xl, centered.w-64), fluid content area. Content area should have its own internal max-width for readability.Not everything needs to be perfectly centered or symmetrical. A page with a large content area and a narrow sidebar is asymmetric but balanced because the content has visual weight. A card grid with 3 columns where the first card is double-width creates intentional asymmetry that draws the eye.
Every page in the app should share:
When building a new page, explicitly reuse patterns from existing pages. Don't invent a new card style when one exists. Don't create a new button variant when primary/secondary/ghost covers the need. Every unique visual pattern adds cognitive load.
Lists of items (pricing plans, feature comparisons, team members) should use identical visual structure with only content changing. When one pricing card has an icon and another doesn't, or one has a colored background and others don't, it creates unintentional hierarchy. If you need to highlight one option, do it with a single differentiator: a border color, a "Popular" badge, or a slight size increase — not three differences at once.
For structured audit checklists (60-second scan and comprehensive), use the design-review skill. The principles in this skill inform what to look for; design-review provides the systematic checklist.