A Material progress indicator (pp_progress/1) — variant="linear" (MUI's LinearProgress) or variant="circular" (MUI's CircularProgress), combined into one component since they share the same value/color contract.

<.pp_progress value={72} />
<.pp_progress />
<.pp_progress variant="circular" value={72} />
<.pp_progress variant="circular" />

value nil (the default) renders the indeterminate/animated form — an unknown-duration loading state, the same distinction PhoenixPaper.Button's loading makes. Circular determinate is a real SVG arc (stroke-dasharray/ stroke-dashoffset computed from value — plain numeric style, not a Tailwind class, so the "no dynamic Tailwind classes" rule doesn't apply to it); circular indeterminate reuses the same bordered-circle animate-spin trick as Button's loading spinner instead of a second SVG, since an indeterminate ring doesn't need to represent a real percentage.