UI and Design System

UI and Design System

Herald's UI is built in SwiftUI with a single design system, MailTheme, that provides colors, spacing, and typography.

MailTheme

MailTheme (Herald/Design/MailTheme.swift:18) is the single source of truth for design tokens:

• Status colors — Unread (accent), read, starred, flagged
• Mailbox palette — Colors assigned to each mailbox (Inbox → blue, Sent → green, etc.) via MailboxColorAssignment (Herald/Design/MailboxColorAssignment.swift:10)
• Spacing — MailTheme.Spacing (enum, line 170) with named sizes (xs, sm, md, lg)
• Radius — MailTheme.Radius (line 194) for corner radii
• Typography — MailTheme.Typography (line 205) for font scales
• Animation — MailTheme.Animation (line 217) for motion curves and durations

All new UI reads from these tokens; no raw Color(hex:), padding() with literal numbers, or font() with Font.system(size: ...).

View components

• ConversationListView (Herald/Views/ConversationListView.swift:45) — The middle pane, showing conversations in a mailbox with search filtering.
• ConversationRow (ConversationListView.swift:451) — A single conversation row with subject, participants, date, and snippet.
• ThreadMessageListView (ConversationListView.swift:239) — Messages in the selected conversation, threaded.
• DraftListView (Herald/Views/DraftListView.swift:12) — A list of in-progress drafts.
• ComposeView (Herald/Compose/ComposeWindow.swift:67) — The compose window UI.

Views hold only transient UI state; app state lives in MailViewModel and ComposeViewModel (@Observable) and is read through the environment.

Accessibility

Rows, chips, and controls carry VoiceOver labels; colors are never the only signal (the unread dot, star, and status chips have text or symbol equivalents); spacing and type come from the tokens so Dynamic Type and contrast stay consistent. The conventions note .memory/conventions/Herald Design System and Accessibility.md is the rule set new UI is reviewed against.

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Last updated: 2026-08-19 — UI and design system; fact-checked against the code for v0.3.0