diff --git a/docs/superpowers/specs/2026-05-31-mobile-camera-button-design.md b/docs/superpowers/specs/2026-05-31-mobile-camera-button-design.md
new file mode 100644
index 0000000..ce8ad00
--- /dev/null
+++ b/docs/superpowers/specs/2026-05-31-mobile-camera-button-design.md
@@ -0,0 +1,94 @@
+# Design: Mobile "Open Camera" Button
+
+**Date:** 2026-05-31
+**Status:** Approved, pending implementation plan
+
+## Summary
+
+Add a button to both the **profile screen** and the **event screen** that, on
+mobile devices only, opens the device's rear camera when tapped. The button is
+a camera-launch affordance — it pops the native camera capture sheet and does
+not process the captured image.
+
+## Motivation
+
+atmo.quest's connect flow relies on scanning a QR code (each profile exposes a
+QR encoding `/c/{did}`). Today users scan with their phone's standalone camera
+app. This feature adds an in-page shortcut to open the camera from the profile
+and event screens on mobile.
+
+## Scope and explicit non-goals
+
+**In scope:** a mobile-only button that opens the native camera capture sheet.
+
+**Explicit non-goal — no QR decode.** Per the product decision during
+brainstorming, the page does **not** process the captured photo. The button is
+a v1 stub / camera-launch affordance, **not a working scanner**. Tapping it
+opens the camera; whatever photo the user takes is discarded.
+
+> Web reality that drove this decision: the only no-dependency way for a web
+> page to open the camera is `<input type="file" capture="environment">`, which
+> opens the **photo-capture sheet**. That sheet takes a still photo and returns
+> it to the input — it does **not** do the live QR detection of the standalone
+> Camera app, and there is no web API to launch that standalone app. Making the
+> button actually connect someone would require adding a decode step (client-
+> side JS QR decode, then redirect to the connect URL). That is a deliberate
+> future enhancement, not part of this work.
+
+## Behavior
+
+- Rendered as a `<label class="btn …">` wrapping a hidden
+  `<input type="file" accept="image/*" capture="environment">`.
+- `capture="environment"` requests the rear camera.
+- Tapping the label opens the native camera capture sheet.
+- The input has **no** change handler — the captured image is not read,
+  uploaded, or decoded.
+
+## Mobile-only visibility
+
+Pure CSS, mirroring the existing `.bottom-nav` convention:
+
+- The button's container class defaults to `display: none`.
+- Inside `@media (max-width: 768px)` it becomes visible.
+
+768px is the app's established mobile breakpoint (see `.bottom-nav` in
+`web/resources/static/css/terminal.css`). No JavaScript, no user-agent
+sniffing. The element is always present in the HTML and simply hidden on
+desktop.
+
+## Reuse
+
+A single shared templ component, `CameraScanButton`, lives in
+`features/common/layouts` alongside `TopNav` / `BottomNav`. Both
+`profile.templ` and `event.templ` invoke it so the markup is defined once.
+
+## Placement
+
+- **Profile** (`features/profile/pages/profile.templ`): directly under the QR
+  flip card (`.profile-flip`), near the top of `.profile-card`.
+- **Event** (`features/event/pages/event.templ`): near the top of
+  `.event-card`, just under the event meta lines.
+
+## Label
+
+`📷 open camera` — honest about what happens, since it does not decode a QR.
+
+## Files touched
+
+- `features/common/layouts/` — new `CameraScanButton` templ component
+  (+ regenerated `*_templ.go`).
+- `features/profile/pages/profile.templ` — invoke the component.
+- `features/event/pages/event.templ` — invoke the component.
+- `web/resources/static/css/terminal.css` — new mobile-only button class.
+- templ regeneration via the project's `templ generate` task.
+
+No Go handler/route changes. No new dependencies.
+
+## Testing
+
+- Verify the button is hidden on desktop widths (> 768px) and visible at
+  ≤ 768px on both screens.
+- On a mobile device / emulated mobile, verify tapping opens the camera capture
+  sheet.
+- Verify existing profile flip and event check-in behavior are unaffected.
+- `templ generate` runs clean; `go build` / existing checks pass.