Hello Calc

# Design Brief: Minimal Monochrome

Monochrome palette with a single accent color, hairline dividers, and generous whitespace.

## Design Tokens

```css
:root {
  --background: #ffffff;
  --surface: #f3f4f6;
  --foreground: #111111;
  --muted-foreground: #6b7280;
  --accent: #1d4ed8;
  --radius: 9999px;
  --font-heading: "Inter", ui-sans-serif, system-ui, sans-serif;
  --font-body: "Inter", ui-sans-serif, system-ui, sans-serif;
}
```

Color area ratio: Background #FFFFFF (~72%) · Surface #F3F4F6 (~12%) · Text #111111 (~6%) · Muted Text #6B7280 (~7%) · Accent #1D4ED8 (~3%). Background and surface dominate the canvas; reserve the accent color for primary buttons and active states.

## Layout & Conversion Structure

- Hero layout: Centered Headline + CTA
- Navigation: Minimal Logo + Action
- Theme & density: Light · Airy
- Border radius & elevation: Pill; no drop shadows—separate layers with hairline borders and whitespace
- Primary visual medium: Pure Typography & Geometry
- Conversion CTA: Direct Input / Instant Try
- Headline hook: Category Positioning Anchor
- Spatial layout notes: Centered Headline + CTA hero structure paired with direct input / instant try CTA and no explicit trust bar.
- Visual summary: Minimal Monochrome (Light canvas, airy density) featuring centered headline + cta layout and pure typography & geometry visuals.

## Avoid

- Multi-stop neon gradients
- Heavy drop shadows
- More than one competing accent color

Implement the UI following the design tokens and layout specifications above: use only these color variables, and reserve the accent color strictly for primary actions and active states. Adopt only this visual style—never copy any reference product’s brand name, logo, copy, or imagery.