Brex UI Skills

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

When to Apply

Reference these guidelines when:

• Building light-mode interfaces

• Creating Brex-inspired design systems

• Implementing UIs with Inter font and 4px grid

Colors

• SHOULD use light backgrounds for primary surfaces

• MUST use #D9D1CF as page background (surface-base )

• MUST use #00070D for primary actions and focus states (accent )

• SHOULD reduce color palette (currently 13 colors detected)

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

Semantic Tokens

Token HEX RGB Usage

surface-base

#D9D1CF rgb(217,209,207) Page background

surface-raised

#FEFEFD rgb(254,254,253) Cards, modals, raised surfaces

surface-overlay

#FF4206 rgb(255,66,6) Overlays, tooltips, dropdowns

text-primary

#D98C71 rgb(217,140,113) Headings, body text

text-secondary

#F3AB84 rgb(243,171,132) Secondary, muted text

text-tertiary

#949397 rgb(148,147,151) Additional text

border-default

#DFE0E1 rgb(223,224,225) Subtle borders, dividers

destructive

#D98C71 rgb(217,140,113) Error states, delete actions

accent

#00070D rgb(0,7,13) Primary actions, links, focus

warning

#FEFEFD rgb(254,254,253) Warning states, cautions

Typography

• MUST use Inter as primary font family

• SHOULD use single font family for consistency

• MUST use 68px / 700 for primary headings

• MUST use 24px / 400 for body text

• MUST limit font weights to: medium, bold, regular

• 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 68px 700 #242528 1

body

Inter 24px 400 #7D7E81 1

text-17px

Inter 17px 500 #3B3A3D 1

text-15px

Inter 15px 400 #5B5B5C 1

text-15px

Inter 15px 400 #545455 1

text-14px

Inter 14px 400 #D98C71 1

text-14px

Inter 14px 400 #949397 1

caption

Inter 13px 400 #F3AB84 1

label

Inter 13px 400 #F2A47B 1

label

Inter 12px 400 #565656 1

Typography Reference

Font Families:

• Inter (used 15x)

Font Sizes: 11px, 12px, 13px, 14px, 15px, 17px, 24px, 68px

Spacing

• MUST use 4px grid for spacing

• SHOULD use spacing from scale: 5px, 60px

• SHOULD use 5px 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: 6px, 7px, 15px

• MUST use 1px border width consistently

• SHOULD use 7px 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: 6px, 7px, 15px

Layout

• MUST design for 1920px base viewport width

• SHOULD use consistent element widths: 10px, 74px, 48px

• SHOULD maintain text-heavy layout with clear hierarchy

• 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-*

Detected Layout Patterns

• Main Content: width: 1920px, height: 969px

• Main Content: width: 1920px, height: 752px

• Header: height: 61px

• Header: height: 50px

• Header: height: 49px

Components

Buttons

Variant Background Text Border Height Radius

Ghost transparent #F3AB84 none

Interactive States

Focus

• MUST use 2px outline with accent color (#00070D )

• MUST use 2px outline-offset

• NEVER remove focus indicators

Hover

• Buttons (primary): lighten background by 10%

• Buttons (secondary): use #FEFEFD background

• List items: use #FEFEFD 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