# GitHub Dark — Design Specification

## Overview
GitHub's homepage is a cinematic dark landing built on deep navy-black (#0d1117). Green CTAs (#2ea043) drive conversion while ambient purple/blue glow effects create dramatic hero sections. The design balances trustworthiness with visual excitement through alternating tinted sections and generous whitespace.

## Color Architecture
### Dark Mode (Canonical)
- **Canvas**: oklch(0.176 0.014 258.4) — deep navy-black
- **Card**: oklch(0.188 0.012 155.9) — green-tinted dark surface
- **CTA Green**: oklch(0.543 0.163 146) — GitHub green for buttons
- **Decorative**: oklch(0.843 0.093 234) — light blue for links and highlights
- **Hero glow**: Radial purple/blue gradient as ambient decoration

## Typography
**Mona Sans** (proprietary). Fallback: **Inter**. Hero titles go up to 4rem/600 weight with -0.03em tracking. Body is 1rem/400 with 1.6 line-height for readability.

## Layout
12-column responsive grid, 1280px max-width. Generous section gaps (80px). Hero section is full-width with floating particle effects.

## Agent Prompt Guide
> Deep navy-black canvas, green CTA buttons, ambient glow hero effects. Large bold typography, generous whitespace, alternating tinted sections.

## Known Gaps
- Mona Sans is proprietary (Inter fallback)
- Animated particle/glow effects are simplified
- Light mode is synthesized from GitHub's actual light theme colors