Two hatches, for two very different sizes. The chart default is a
fine 1 px hairline on a 5 px pitch over a ~22 % base tint — texture over a
translucent bar, read against its neighbours on a tinted plot. opaque is
for the app surface's thin standalone bars and INVERTS that: full-strength
2 px strokes on a 6 px period over a pale ~28 % bar, because a hairline on a
4 px-tall bar is smaller than the diagonal's own antialiasing and smears the
whole bar into a wash.
color accepts anything background-color accepts — hex, var(--metric-x),
or color-mix(…).
Inline-style fill for a rep bar in the performance / focus-metric charts. Concentric reps render as solid fill; eccentric reps render as a 45°-diagonal stripe pattern in the same colour (matches the iOS bar-chart convention so eccentric vs concentric reads at a glance without doubling the legend).