Fe Design

Lingx Frontend Design

Premium, crafted UI for developers and translation managers. Every interface should look designed by a team that obsesses over 1-pixel differences.

Philosophy: Restraint, precision, intentionality. "Expensive" is conveyed through what you DON'T add.

Design Direction (FIXED)

Lingx blends Warmth & Approachability with Utility & Function:

DO NOT reconsider these decisions. Apply them.

Color Tokens (USE THESE)

Primary Palette

Semantic Colors (Translation States)

Usage Rules

• Gray builds structure. Color only for: status, action, error, success
• One accent. Purple is primary. Coral (--accent-warm) only for secondary CTAs
• Semantic only. No decorative color. Every color must communicate meaning

Spacing (4px Grid)

All spacing uses 4px increments. Use Tailwind scale:

Symmetrical padding required. p-4 or px-4 py-3 (when horizontal needs room). Never pt-6 pb-2 px-4.

Component Standards

Sizing (MANDATORY)

Islands (Card Containers)

// Always use .island class for card containers
<div className="island space-y-4 p-6">{/* content */}</div>

The .island class provides:

• bg-card background
• rounded-xl border radius
• Subtle inner-glow shadow (light mode)
• border border-border (dark mode)

Forms (ALWAYS use shadcn Form)

import {
  Form,
  FormControl,
  FormField,
  FormItem,
  FormLabel,
  FormMessage,
} from '@/components/ui/form';

<Form {...form}>
  <FormField
    control={form.control}
    name="fieldName"
    render={({ field }) => (
      <FormItem>
        <FormLabel>Label</FormLabel>
        <FormControl>
          <Input {...field} /> {/* h-11 rounded-xl built-in */}
        </FormControl>
        <FormMessage /> {/* Auto error icon */}
      </FormItem>
    )}
  />
</Form>;

Use mode: 'onTouched' in useForm for errors after blur.

Typography

Font Stack

• UI text: Geist (via font-sans)
• Data/code: Geist Mono (via font-mono)

Hierarchy

Data Display

• Translation keys: font-mono text-sm
• IDs, codes, timestamps: font-mono tabular-nums
• Numbers in tables: tabular-nums for alignment

Animation

Entry Animations

// Staggered fade-in for page content
<div className="animate-fade-in-up stagger-1">First element</div>
<div className="animate-fade-in-up stagger-2">Second element</div>
<div className="animate-fade-in-up stagger-3">Third element</div>
// ... up to stagger-6

Transitions

Rules

• No spring/bounce in enterprise UI
• No gradients for decoration
• Subtle .card-hover for elevation on hover

Icons

Use lucide-react (included via shadcn).

import { Plus, Settings, ChevronRight } from 'lucide-react';

<Button>
  <Plus className="size-4.5" />
  Add Key
</Button>;

Rules:

• Icons clarify, not decorate. If removing loses no meaning, remove it.
• Standalone icons get subtle background containers
• Default size in buttons: size-4.5 (18px)

Tailwind v4 Syntax

CRITICAL: Lingx uses Tailwind v4. Avoid v3 syntax errors:

Spacing scale: value × 4px (e.g., w-50 = 200px, size-200 = 800px)

Layout Patterns

Page Structure

<div className="space-y-6">
  {/* Page header */}
  <div className="flex items-center justify-between">
    <h1 className="text-2xl font-semibold -tracking-tight">Page Title</h1>
    <Button>
      <Plus className="size-4.5" />
      Action
    </Button>
  </div>

  {/* Stats row */}
  <div className="grid grid-cols-4 gap-4">
    <StatCard />
    <StatCard />
    <StatCard />
    <StatCard />
  </div>

  {/* Main content island */}
  <div className="island p-6">{/* content */}</div>
</div>

Stat Card

<div className="island animate-fade-in-up stagger-1 p-6">
  <div className="flex items-center justify-between">
    <span className="text-muted-foreground text-sm">Label</span>
    <ArrowUpRight className="text-muted-foreground size-4" />
  </div>
  <div className="mt-2 text-4xl font-semibold tabular-nums">42,847</div>
  <div className="text-success mt-1 flex items-center gap-1 text-sm">
    <TrendingUp className="size-3.5" />
    <span>12% vs last week</span>
  </div>
</div>

Empty States

Don't leave empty space. Options:

1. Helpful guidance - "Get started by..." with action button
2. Illustration - Minimal, on-brand empty state graphic
3. Condensed layout - Reduce columns, adjust grid
4. Related content - Activity feed, tips, documentation links

Anti-Patterns (NEVER DO)

Banned

• ❌ Dramatic shadows (shadow-2xl, shadow-[0_25px_50px...])
• ❌ Large radius on small elements (rounded-2xl on buttons)
• ❌ Asymmetric padding without reason
• ❌ Pure white cards on colored backgrounds (use bg-card)
• ❌ Thick borders (2px+) for decoration
• ❌ Excessive spacing (margins > 48px between sections)
• ❌ Spring/bouncy animations
• ❌ Gradients for decoration
• ❌ Multiple accent colors
• ❌ Native form elements (<select>, <input type="date">)
• ❌ Color-coding everything (use gray, reserve color for meaning)

Always Question

• "Does this element feel crafted or default?"
• "Am I adding this for visual fill or function?"
• "Is every color earning its place?"
• "Are all elements on the 4px grid?"

Quick Reference

// Standard island
<div className="island p-6 space-y-4 animate-fade-in-up">

// Button with icon
<Button className="h-11"><Plus className="size-4.5" />Label</Button>

// Input
<Input className="h-11 rounded-xl bg-card" />

// Muted text
<span className="text-sm text-muted-foreground">Secondary info</span>

// Translation key
<code className="font-mono text-sm">namespace.key</code>

// Status badge
<Badge variant="success">Complete</Badge>

// Stats number
<span className="text-4xl font-semibold tabular-nums">1,234</span>

// Section spacing
<div className="space-y-6">

// Grid of cards
<div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-4">

Developer Patterns

For developer-facing features, leverage familiar patterns:

Balance familiarity with design system aesthetics.

The Standard

Every interface should feel crafted, not generated. Premium is conveyed through:

• Restraint — What you don't add matters more
• Precision — Every pixel on the grid
• Intentionality — Every element earns its place
• Consistency — Same patterns, same treatment, everywhere

The goal: intricate minimalism with warmth. Same quality bar as Linear, Stripe, Notion.

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