Users want to see all matchup guides simultaneously on a sideboard guide detail page, instead of selecting one at a time. This was a feature in V1. Feature: A toggleable "multi-matchup view" mode on desktop. When activated, DeckV2ListView is frozen/sticky on the left, and all matchup guides are displayed as GuideV2Listview instances in a horizontally scrollable carousel to the right. SideboardMatchupSelector is hidden since all matchups are visible. Editing: Owners can edit in multi-matchup mode. Clicking a guide sets it as selectedMatchupGuideId, enabling editing for that guide only. Non-owner viewers can see all guides but cannot edit. MatchupPrimer: Accessed via a new button in each GuideV2Listview that opens a Shadcn Dialog/modal. Not rendered inline in multi-matchup mode. Below carousel: SideboardPrimer, DeckAnalysisSection, DeckSampleHandSection, TokensSection, SideboardFAQ, DeckKeepOrMullSection, YouTubeEmbed. --- FILES TO MODIFY: sideboard-view.tsx — conditional multi-matchup layout (lines 885-1033) multi-matchup-carousel.tsx — NEW: DeckV2ListView (sticky left) + N GuideV2ListViews in ScrollArea guide-v2-listview.tsx — add MatchupPrimer dialog button deck-ui-store.ts — add isMultiMatchupView persisted toggle --- ACCEPTANCE CRITERIA: Toggle button on desktop (hidden below xl), always visible even with 0 matchups View preference persisted across sessions DeckV2Listview sticky on left, all guides in horizontal ScrollArea Uniform guide widths (min-w-[280px] max-w-[350px] w-[300px]) Clicking a guide enables editing for owners (visual ring indicator) "Add Matchup" button at end of carousel for owners MatchupPrimer button on each guide opens Shadcn Dialog Supplementary sections below carousel No regressions in single-matchup flow Mobile view unchanged Type-check passes Complexity: Medium — no backend changes, all core components exist. Related: "matchups side-by-side" post