body { font-family: system-ui, -apple-system, Arial, sans-serif; margin: 0; }
.topbar { padding: 12px 16px; border-bottom: 1px solid #ddd; display: flex; gap: 16px; align-items: center; }
.nav button { margin-right: 8px; padding: 8px 10px; cursor: pointer; }
main { padding: 16px; }
.card { border: 1px solid #ddd; padding: 12px; border-radius: 8px; max-width: 900px; }
.small { color: #666; font-size: 14px; }