diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..1cacf13
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,12 @@
+# public/projects.ts embeds literal NUL bytes on purpose: the namespace-group
+# sentinels ACTIVE_GROUP_KEY = '\0active' and OTHER_GROUP_KEY = '\0other' are
+# prefixed with NUL so they can never collide with a real `First.Second` key.
+#
+# git classifies any file containing NUL as binary, so `git diff`/`git show`
+# print "Binary files differ" and review of this file is impossible. The `diff`
+# attribute tells git to diff it as text anyway. It does NOT set `text`, so
+# nothing is line-ending-normalised and the bytes on disk are untouched.
+#
+# Same trap in the shell: `grep` prints only "Binary file ... matches" and looks
+# like a no-match. Use `grep -a` on this file.
+public/projects.ts diff
diff --git a/public/projects.ts b/public/projects.ts
index 8bc9ad5..490e7ef 100644
Binary files a/public/projects.ts and b/public/projects.ts differ
diff --git a/public/style.css b/public/style.css
index 08e2327..7db0aa1 100644
--- a/public/style.css
+++ b/public/style.css
@@ -1541,13 +1541,17 @@ body {
   white-space: nowrap;
 }
 
-/* Branch chip */
+/* Branch chip — same geometry and border as every other chip in the panel. It was
+   the odd one out: no border, no mono face, and 1px tighter all round, so the
+   detail header's branch did not match the branch chips in the worktree list. */
 .proj-branch {
-  font-size: 11px;
+  font-family: var(--mono-font);
+  font-size: 11.5px;
   color: var(--accent);
   background: var(--accent-soft);
-  border-radius: 5px;
-  padding: 2px 7px;
+  border: 1px solid rgba(227, 166, 74, 0.36);
+  border-radius: 6px;
+  padding: 3px 9px;
   white-space: nowrap;
   flex: none;
 }
@@ -1806,18 +1810,22 @@ body {
   flex: none;
 }
 
-/* The design has exactly two button roles: filled accent for the action that
-   commits a form (Fetch, Create Worktree), and this ghost for anything that only
-   opens or reveals. Everything in a worktree's action rail is a ghost — including
-   the ✕, which previously had no rule at all and rendered as a raw grey OS button. */
+/* Role 2 of 2 — the ghost. The design has exactly two button roles: filled accent
+   for the action that commits a form (Fetch, Create Worktree), and this outline for
+   anything that only opens, reveals or toggles. ONE geometry for every one of them:
+   the role had drifted to three different sizes across the panel, all at
+   full-strength --text instead of the muted label the design asks for.
+   Every outline button in the panel is listed here, and nowhere else, so a new one
+   cannot quietly pick its own size again. */
 .proj-wt-open,
 .proj-wt-remove,
-.proj-wt-prune {
+.proj-wt-prune,
+.proj-diff-toggle {
   font: inherit;
-  font-size: 11.5px;
+  font-size: 12.5px;
   cursor: pointer;
-  padding: 4px 12px;
-  border-radius: 6px;
+  padding: 7px 15px;
+  border-radius: 7px;
   border: 1px solid var(--border-strong);
   background: transparent;
   color: var(--text-dim);
@@ -1825,24 +1833,27 @@ body {
 
 .proj-wt-open:hover,
 .proj-wt-remove:hover,
-.proj-wt-prune:hover {
+.proj-wt-prune:hover,
+.proj-diff-toggle:hover {
   border-color: var(--accent);
   color: var(--accent);
 }
 
 .proj-wt-open:focus-visible,
 .proj-wt-remove:focus-visible,
-.proj-wt-prune:focus-visible {
+.proj-wt-prune:focus-visible,
+.proj-diff-toggle:focus-visible {
   outline: 2px solid var(--text);
   outline-offset: 2px;
 }
 
-/* Square icon variant — same role, just not a word. Height matches Open so the
-   two sit flush in the rail. */
+/* Square icon variant — same role, just not a word. Keeps the shared height
+   (12.5px line + 7px padding twice) so it sits flush beside Open in the rail
+   rather than stretching the row. */
 .proj-wt-remove {
-  width: 26px;
-  padding: 0;
-  line-height: 24px;
+  width: 33px;
+  padding: 7px 0;
+  line-height: 1;
   text-align: center;
   flex: none;
 }
@@ -2513,26 +2524,12 @@ body {
   cursor: not-allowed;
 }
 
-/* Role 2 — ghost, for anything that only reveals or toggles. */
-.proj-diff-toggle {
-  font: inherit;
-  font-size: 12.5px;
-  cursor: pointer;
-  padding: 7px 15px;
-  border-radius: 7px;
-  border: 1px solid var(--border-strong);
-  background: transparent;
-  color: var(--text-dim);
-}
-
-.proj-diff-toggle:hover {
-  border-color: var(--accent);
-  color: var(--accent);
-}
+/* Role 2 (the ghost, incl. .proj-diff-toggle) is defined once, with the worktree
+   action rail — see "Role 2 of 2" above. Nothing for it here on purpose: a second
+   block at equal specificity is how the role drifted to three sizes before. */
 
 .proj-wt-submit:focus-visible,
-.proj-fanout-submit:focus-visible,
-.proj-diff-toggle:focus-visible {
+.proj-fanout-submit:focus-visible {
   outline: 2px solid var(--text);
   outline-offset: 2px;
 }
diff --git a/src/http/projects.ts b/src/http/projects.ts
index 875948b..dadaff5 100644
--- a/src/http/projects.ts
+++ b/src/http/projects.ts
@@ -209,7 +209,14 @@ async function readSyncState(repoPath: string): Promise<SyncState> {
   if (counts.ahead !== undefined) state.ahead = counts.ahead
   if (counts.behind !== undefined) state.behind = counts.behind
   if (lastFetchMs !== undefined) state.lastFetchMs = lastFetchMs
-  if (headText !== null && parseGitHead(headText) === null) state.detached = true
+  if (headText !== null && parseGitHead(headText) === null) {
+    state.detached = true
+    // A detached HEAD file holds the raw object id and nothing else. It is the
+    // only identity the cell can show — there is no branch name — and it costs
+    // no extra I/O, since the file is already read above for the detached test.
+    const sha = headText.trim()
+    if (/^[0-9a-f]{7,40}$/i.test(sha)) state.head = sha.slice(0, 7)
+  }
   return state
 }
 
diff --git a/src/types.ts b/src/types.ts
index 7ee8b12..c7e5f96 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -395,6 +395,7 @@ export interface SyncState {
   behind?: number; // commits on @{u} not on HEAD — trust only with a fresh lastFetchMs
   lastFetchMs?: number; // FETCH_HEAD mtime; undefined ⇒ never fetched
   detached?: boolean; // HEAD is not on a branch ⇒ no branch, no ahead/behind
+  head?: string; // short sha, ONLY when detached — the cell's sole identity
 }
 
 /** w6/G7: the git state of ONE worktree, fetched lazily per row.
diff --git a/test/projects-panel.test.ts b/test/projects-panel.test.ts
index 499eccf..a575a55 100644
--- a/test/projects-panel.test.ts
+++ b/test/projects-panel.test.ts
@@ -799,6 +799,18 @@ describe('makeSyncBand (w6 G3)', () => {
     expect(btn.disabled).toBe(true)
   })
 
+  it('shows the short sha on a detached HEAD — it is the only identity left', () => {
+    const b = band({ detached: true, head: 'deadbee' })!
+    expect(b.querySelector('.proj-sync-upstream')!.textContent).toBe('deadbee')
+    expect(b.querySelector('.proj-sync-detached')!.textContent).toBe('detached HEAD')
+  })
+
+  it('still renders the detached chip when the sha could not be read', () => {
+    const b = band({ detached: true })!
+    expect(b.querySelector('.proj-sync-upstream')).toBeNull()
+    expect(b.querySelector('.proj-sync-detached')).not.toBeNull()
+  })
+
   it('names the upstream so the arrows are not floating numbers', () => {
     const b = band({ upstream: 'origin/develop', ahead: 9, behind: 0, lastFetchMs: FRESH })!
     expect(b.textContent).toContain('origin/develop')
diff --git a/test/projects.test.ts b/test/projects.test.ts
index 75f5687..28c7fd8 100644
--- a/test/projects.test.ts
+++ b/test/projects.test.ts
@@ -662,6 +662,21 @@ describe('buildProjectDetail — sync state (w6 G1)', { timeout: 30_000 }, () =>
     expect(d!.branch).toBeUndefined()
     expect(d!.sync!.ahead).toBeUndefined()
     expect(d!.sync!.behind).toBeUndefined()
+    // With no branch name the short sha is the only identity the panel can show.
+    // Read out of the .git/HEAD text already loaded for the detached test — no
+    // extra git call.
+    expect(d!.sync!.head).toBe(stdout.trim().slice(0, 7))
+  })
+
+  it('does not report a head sha when HEAD is on a branch', async () => {
+    if (!(await gitAvailable())) return
+    const repo = path.join(tmp, 'g1-attached-head')
+    await initRepo(repo)
+    await commit(repo, 'a.txt', 'only')
+
+    const d = await buildProjectDetail(makeCfg({}), repo, [])
+    expect(d!.sync!.detached).not.toBe(true)
+    expect(d!.sync!.head).toBeUndefined()
   })
 
   it('counts dirty files instead of only flagging them', async () => {