Replit UI Skills

Opinionated constraints for building Replit-style interfaces with AI agents.

When to Apply

Reference these guidelines when:

• Building light-mode interfaces

• Creating Replit-inspired design systems

• Implementing UIs with Inter font and 4px grid

Colors

• SHOULD use light backgrounds for primary surfaces

• MUST use #F8F8F8 as page background (surface-base )

• MUST use #9266E6 for primary actions and focus states (accent )

• SHOULD reduce color palette (currently 26 colors detected)

• MUST maintain text contrast ratio of at least 4.5:1 for accessibility

Semantic Tokens

Token HEX RGB Usage

surface-base

#F8F8F8 rgb(248,248,248) Page background

surface-raised

#1C4B39 rgb(28,75,57) Cards, modals, raised surfaces

surface-overlay

#E1EAE7 rgb(225,234,231) Overlays, tooltips, dropdowns

text-primary

#769E8E rgb(118,158,142) Headings, body text

text-secondary

#8F9A96 rgb(143,154,150) Secondary, muted text

text-tertiary

#BBBFBB rgb(187,191,187) Additional text

border-default

#EEEEEE rgb(238,238,238) Subtle borders, dividers

accent

#9266E6 rgb(146,102,230) Primary actions, links, focus

destructive

#DE4409 rgb(222,68,9) Error states, delete actions

Typography

• MUST use Inter as primary font family

• SHOULD use single font family for consistency

• MUST use 31px / semi_bold for primary headings

• MUST use 13px / 400 for body text

• SHOULD reduce font weights (currently 4 detected)

• MUST use text-balance for headings and text-pretty for body text

• SHOULD use tabular-nums for numeric data

• NEVER modify letter-spacing unless explicitly requested

Text Styles

Style Font Size Weight Color Count

heading-1

Inter 31px semi_bold #3D3D3D 1

heading-2

Inter 30px 500 #434B46 1

text-22px

Inter 22px 500 #515152 1

text-18px

Inter 18px 500 #333333 1

text-15px

Inter 15px 400 #A7A7AA 1

text-14px

Inter 14px 400 #6D6F6E 1

text-14px

Inter 14px 300 #616362 1

text-14px

Inter 14px 400 #909194 1

text-14px

Inter 14px 300 #7A7A7B 1

text-14px

Inter 14px 400 #757575 1

Typography Reference

Font Families:

• Inter (used 64x)

Font Sizes: 3px, 4px, 5px, 6px, 7px, 8px, 11px, 13px, 14px, 15px, 18px, 22px, 30px, 31px

Spacing

• MUST use 4px grid for spacing

• SHOULD use spacing from scale: 1px, 2px, 3px, 4px, 5px, 8px, 12px, 13px

• SHOULD use 2px as default gap between elements

• NEVER use arbitrary spacing values (use design scale)

• SHOULD maintain consistent padding within containers

Borders

• MUST use border-radius from scale: 0px, 1px, 2px, 3px, 4px, 5px, 6px, 7px, 9px, 10px, 13px, 15px, 16px, 18px, 45px

• SHOULD use 45px+ radius for pill-shaped elements

• MUST use 1px border width consistently

• SHOULD use 3px as default border-radius

• NEVER use arbitrary border-radius values (use design scale)

• SHOULD use subtle borders (1px) for element separation

Border Radius Reference

Scale: 0px, 1px, 2px, 3px, 4px, 5px, 6px, 7px, 9px, 10px, 13px, 15px, 16px, 18px, 45px

Layout

• MUST design for 1920px base viewport width

• SHOULD use consistent element widths: 14px, 6px, 10px, 4px, 21px

• NEVER use h-screen , use h-dvh for full viewport height

• MUST respect safe-area-inset for fixed elements

• SHOULD use size-* for square elements instead of w-*

• h-*

Components

Buttons

Variant Background Text Border Height Radius

Ghost transparent #769E8E none

Interactive States

Focus

• MUST use 2px outline with accent color (#9266E6 )

• MUST use 2px outline-offset

• NEVER remove focus indicators

Hover

• Buttons (primary): lighten background by 10%

• Buttons (secondary): use #1C4B39 background

• List items: use #1C4B39 background

Disabled

• MUST use opacity: 0.5

• MUST use cursor: not-allowed

Interaction

• MUST use an AlertDialog for destructive or irreversible actions

• SHOULD use structural skeletons for loading states

• MUST show errors next to where the action happens

• NEVER block paste in input or textarea elements

• MUST add an aria-label to icon-only buttons

Animation

• NEVER add animation unless it is explicitly requested

• MUST animate only compositor props (transform , opacity )

• NEVER animate layout properties (width , height , top , left , margin , padding )

• SHOULD use ease-out on entrance animations

• NEVER exceed 200ms for interaction feedback

• SHOULD respect prefers-reduced-motion

Performance

• NEVER animate large blur() or backdrop-filter surfaces

• NEVER apply will-change outside an active animation

• NEVER use useEffect for anything that can be expressed as render logic