Post-it diagram kit

A small, hand-drawn "whiteboard sticky" style for SolidSyslog diagrams, used in the docs, the site, and articles. It keeps architecture pictures friendly and quick to read: colour tells you the kind of thing, the arrow tells you the relationship.

The vocabulary

Colour	Means	Example
Yellow	Core / facade — the thing you call	SolidSyslog
Green	A role (a vtable / extension point)	Sender, Store, Buffer
Blue	A backend that realises a role	StreamSender, BlockStore
Pink	Something you inject	Config, a clock callback, the platform socket

Arrow	Means
Solid head	uses / depends on
Hollow head	realises (a backend realises a role's vtable)
Pink dashed	you inject this across the boundary

Authoring a diagram

1. Start from architecture.svg: copy it and edit the stickies. Each sticky is a shadowed <rect> plus a rotated <g> of text; a small rotation (±2°) is what sells the hand-drawn feel.
2. Keep the palette and markers identical to postit-defs.svg: that consistency is the whole point. If you want to retune the look (roughness, shadow, arrowheads), change it in postit-defs.svg first, then carry it into the diagrams.
3. Aim for ~10–12 stickies. If it needs more, it probably wants to be two diagrams.

One exception: architecture-overview.svg is generated, not hand-drawn — its layout (boundary crossings, fan-out lines) is computed. Edit scripts/gen_architecture_overview.py and re-run it; do not hand-edit the SVG. It keeps the same palette but drops the sticky rotation/shadow for a precise architectural read, and colours by provenance (Core / adapter / third party) with the boundary marking Core.

Why the defs are copied into each diagram

Published diagrams inline the shared <defs> (filters, markers) rather than referencing postit-defs.svg. GitHub's Markdown renderer sanitises cross-file SVG references, so a self-contained file is the only thing guaranteed to render in the repo, the docs site, and on the web. postit-defs.svg stays the canonical source you copy from and the one place to tune the style.

For LinkedIn or slides, export the SVG to PNG at publish time; SVG isn't accepted in LinkedIn articles.