Inbox

Anatomy. Clickable StackedList of conversations (a span-5 rail, the open one marked with an Open badge) beside the open thread of flat message Cards, its subject and count Badge, and the controlled reply composer (span 7); pressing a conversation opens it and Send appends the reply. The panes are a Row stacks that stacks once the section is md wide or narrower, and a half-typed reply keeps its text and focus across the switch.