sx for a button's inline text label — the theme font at subtitle2 size, single line, no
uppercasing. A bare MUI icon button leaves text children unstyled (browser serif, default size),
so any button that renders a label as content applies this. Mirrors LabelIcon's text styling and
is the single source of truth for ExhibitPopupIconButton and CommandButton (leaf).
sxfor a button's inline text label — the theme font atsubtitle2size, single line, no uppercasing. A bare MUI icon button leaves text children unstyled (browser serif, default size), so any button that renders a label as content applies this. MirrorsLabelIcon's text styling and is the single source of truth forExhibitPopupIconButtonandCommandButton(leaf).