B-VTB1-mermaid-dark-edge-label-background
State: promoted/task
Under mermaid’s dark theme an edge label renders on an opaque mid-grey plate, markedly lighter
than the surrounding surface. It is mermaid’s own edgeLabelBackground, not consumer code.
Seen in the flows designer’s diagram drawer after T-RJCY-mermaid-block-source-prop-flows moved
it onto MermaidBlock: the edge label sits on a grey box, while the same label text in the vue-flow
canvas directly above renders as plain text on the surface. The light (neutral) theme does not
show it.
This reaches every consumer of MermaidBlock in dark mode, so it belongs to the shared component
rather than to one product. Suggested shape: a companion rule shipped with the renderer’s theme that
neutralises the dark edgeLabel background against the surface token, so no product patches its own
drawer.