// Class rules — reusable visual bundles applied with .name.
.thin { stroke: #444; stroke-width: 1; }
.bold { font-weight: bold; }
.power { stroke: red; stroke-width: 2; }
.warn { stroke: orange; }
.ghost { opacity: 0.3; }
a |box| .thin "thin"
b |box| .bold "bold"
c |box| .power "power"
d |box| .warn "warn"
e |box| .ghost "ghost"