System Message

SystemMessage is the centered line in a transcript for an event that is not a person's message: someone joined, someone left, the call connected, a note from the system. It is plain caption text at the subtle tier, with no side rule and no surface, so it never reads as the caller or the agent speaking. An optional time follows the text. It is a container, not an overlay: it never portals, and it carries no role or live region. The scroll container that holds the transcript owns the log role. SystemMessage formats nothing. A Time with format and no children writes the instant in the locale and time zone of the nearest LocaleProvider, 24-hour by default (ADR 0024). The line is centered in the inline axis. Alignment uses logical properties, so a right-to-left page keeps it centered with no extra rule. Long text wraps onto balanced, centered lines and breaks anywhere, so an unbroken string never overflows. The time sits after the text, 4px away, and wraps to its own centered line before it is cut. The line owns no space above or below it, and its block padding is the same on both sides. Inside MessageList it sits 24px from the item before and the item after, whatever they are. Stacked by hand, put the space on the container. The text sits 8px from the list edge. The root is a container. It drops style, every on* handler, and the reserved state attributes. tabIndex is allowed only as -1, so a list can move focus to a line.