Mainline

Mainline is a polished source-hosting console that takes its visual cues directly from GitHub. The Home overview opens with a four-tile KPI strip, a 53-week contribution heatmap with a vertical year selector (4 years pre-seeded) styled like the green GitHub graph, a language footprint card, a draggable Pinned repositories grid (max 6, dnd-kit) and a GitHub-style monthly Contribution activity timeline. Repositories ship with a grid / list toggle, language and visibility filters, and clickable cards that route to a full repository detail page (tabs, file tree mock, README, About sidebar with releases and contributors) — all of it modeled on the GitHub repo layout. Pull requests and Issues queue rows with labels, CI status, branch arrows and priority dots, all filterable by tab, role and repo.

Three secondary surfaces flesh out the workflow, also borrowed from GitHub: a Notifications inbox with Inbox / Saved / Done buckets and reason filters, a New repository form with Owner / Visibility / Template / README / gitignore / license / default branch sections, and a Settings page with a sticky grouped nav (Public profile, Account, Appearance, Accessibility, Notifications, Access group, Code group) and a fully-wired Public profile form. The header bell and `+ New repository` CTA route directly to those pages, and a Customize your pins modal lets you rebuild the pinned list with a search-filtered checklist capped at six.

Everything runs client-side against a Zustand store seeded with realistic mock data — 14 repositories, 12 pull requests, 12 issues, 15 curated activities plus 100+ procedurally generated ones across three months, 9 topics and 15 notifications. Dates flow through `date-fns-tz`'s `formatInTimeZone(..., 'UTC', ...)` to keep SSR markup hydration-stable. Drop in your real backend by replacing the mock imports — every store action stays compatible. It's GitHub's collaboration surface, packaged as a Square UI Pro template you can rebrand in an afternoon.