The 24-hour clock has no period selector beside the hour and minute boxes, so M3 widens them to 114px; AM/PM takes its own tertiary-container rather than borrowing the boxes' primary-container; a disabled period button uses M3's 12% disabled container, not 10%; and the pair is a radio group, which is what M3's labelling table asks for, so the arrows move between AM and PM. Plan step 20, findings IN-10, IN-11, IN-26 and IN-27. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9