---
name: html-draft
description: Use when user wants a standalone HTML diagram in flat engineering blueprint style — architecture diagrams, system flows, technical spec sheets, component maps. Generates one HTML file using Tailwind v4 (browser CDN) for layout and D3 v7 (CDN) for SVG diagrams. User-invoked only — do NOT auto-trigger. Triggers on "/html-draft", "сделай blueprint", "технический чертёж", "архитектурная схема", "инженерная схема", "blueprint diagram", "engineering blueprint", "technical spec sheet", "architecture diagram", "system flow diagram".
---
# html-draft — Flat Engineering Blueprint Diagrams
Generate one HTML page that renders a technical diagram in a strict flat-blueprint aesthetic — the look of a printed engineering specification sheet, not a marketing landing.
**Stack:** Tailwind v4 via `@tailwindcss/browser` CDN for layout + utilities, D3 v7 via jsDelivr CDN for SVG-based diagrams (nodes, connectors, layouts, animations).
**Use this when** the user wants an architecture diagram, system flow, technical spec sheet, or component map as a standalone HTML artifact (suitable for slides, reports, exports).
**Don't use this for:**
- Inline schemas inside markdown documents — use a mermaid renderer instead
- Newspaper / reading-first single-column pages with monospace ink-on-cream feel
- Multi-section interactive explainers with pill navigation
## Design philosophy
Precise. Objective. High data-ink ratio (Tufte). Every pixel earns its place; nothing decorative. The stack is modern (Tailwind + D3) but the output looks like a printed engineering doc.
## Visual rules
### Flat, outlined, monochrome
- **No** drop shadows, gradients, glassmorphism, blur, rounded buttons
- 1px or 2px solid borders define structure
- White content blocks on a light-gray canvas
- Accent: black, or a single semantic color (red for error, etc.) used sparingly
- Do **not** import a Tailwind component library — pure utility classes only
### Design tokens (declared once via `@theme`)
```css
@theme {
--color-c-bg: #f8fafc; /* page background — slate-50 */
--color-c-canvas: #ffffff; /* diagram canvas */
--color-c-border: #cbd5e1; /* slate-300 */
--color-c-text-main: #0f172a; /* slate-900 */
--color-c-text-sub: #64748b; /* slate-500 */
--color-c-accent: #b91c1c; /* red-700 — semantic only */
--font-ui: system-ui, -apple-system, 'Segoe UI', sans-serif;
--font-mono: 'SF Mono', Monaco, Consolas, monospace;
}
```
Tokens become Tailwind utilities automatically: `bg-c-canvas`, `border-c-border`, `text-c-text-sub`, `font-mono`.
### Typography
- Headings, labels: sans-serif (`font-ui`)
- Data, paths, code, IDs, version strings: `font-mono`
- Never link Google Fonts — the system stack already covers both roles
### Layout
- Whole diagram lives in a `.diagram-canvas` — bordered box with generous padding (`p-8` or more)
- Header: title + UPPERCASE subtitle, separated from body by a 1px bottom border
- Strict alignment via `grid` / `flex` utilities; no eyeballing
### Connectors
- Thin straight or orthogonal lines (1px solid)
- Dashed lines for abstract / logical relationships, never structural ones
- D3-rendered SVG for non-orthogonal arrows; Tailwind `border-t` / `border-l` for orthogonal CSS connectors
### Icons & badges
- Icons: simple stroke SVG (no fills, no detail) drawn via D3 or inline `