Plan step 36. <x-button-group> renders data-md-button-group (standard or
connected), data-md-size, data-md-shape and, with a selection,
data-md-selection and data-md-selection-required. button-group.css now
also draws the standard group: its gaps per size, the square corner scale
it hands its buttons, and the press expansion that widens a pressed label
button while its neighbours give way. groups.css keeps only the split
button until that is rewritten too.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9
