diff --git a/apps/planner/app/components/ParticipantAvatars.tsx b/apps/planner/app/components/ParticipantAvatars.tsx
new file mode 100644
index 0000000..d821d05
--- /dev/null
+++ b/apps/planner/app/components/ParticipantAvatars.tsx
@@ -0,0 +1,87 @@
+import { useEffect, useRef, useState } from "react";
+import { useTranslation } from "react-i18next";
+import { Avatar, Badge } from "@trails-cool/ui";
+import type { Participant } from "~/lib/use-participants";
+
+interface ParticipantAvatarsProps {
+  participants: Participant[];
+  /** Called when the local participant commits a new display name. */
+  onRenameLocal?: (name: string) => void;
+}
+
+/**
+ * Presentational participant strip: a colored Avatar per participant, the
+ * local user's name inline-editable, and a Host badge. Driven entirely by the
+ * plain `participants` array so it renders in the /dev/ui gallery without a
+ * live session.
+ */
+export function ParticipantAvatars({
+  participants,
+  onRenameLocal,
+}: ParticipantAvatarsProps) {
+  const { t } = useTranslation("planner");
+  const [editing, setEditing] = useState(false);
+  const [value, setValue] = useState("");
+  const inputRef = useRef<HTMLInputElement>(null);
+
+  useEffect(() => {
+    if (editing && inputRef.current) {
+      inputRef.current.focus();
+      inputRef.current.select();
+    }
+  }, [editing]);
+
+  const startEditing = (name: string) => {
+    setValue(name);
+    setEditing(true);
+  };
+
+  const commit = () => {
+    onRenameLocal?.(value);
+    setEditing(false);
+  };
+
+  return (
+    <div className="flex items-center gap-2">
+      {participants.map((p) => (
+        <div key={p.clientId} className="flex items-center gap-1.5">
+          <Avatar name={p.name} color={p.color} size="sm" />
+          {p.isLocal && editing ? (
+            <input
+              ref={inputRef}
+              type="text"
+              value={value}
+              onChange={(e) => setValue(e.target.value)}
+              onBlur={commit}
+              onKeyDown={(e) => {
+                if (e.key === "Enter") commit();
+                else if (e.key === "Escape") setEditing(false);
+              }}
+              maxLength={20}
+              className="w-24 rounded border border-border bg-bg-raised px-1.5 py-0.5 text-base text-text-hi focus:border-accent focus:outline-none sm:text-xs"
+            />
+          ) : (
+            <button
+              type="button"
+              onClick={p.isLocal ? () => startEditing(p.name) : undefined}
+              className={
+                p.isLocal
+                  ? "cursor-pointer text-xs text-text-hi hover:underline"
+                  : "cursor-default text-xs text-text-md"
+              }
+              title={p.isLocal ? t("participants.editName") : p.name}
+            >
+              {p.name}
+              {p.isLocal && (
+                <span className="ml-0.5 text-text-lo">
+                  {t("participants.you")}
+                </span>
+              )}
+            </button>
+          )}
+          {p.isHost && <Badge tone="accent">{t("participants.host")}</Badge>}
+        </div>
+      ))}
+    </div>
+  );
+}
diff --git a/apps/planner/app/components/ParticipantList.tsx b/apps/planner/app/components/ParticipantList.tsx
deleted file mode 100644
index 154c3d9..0000000
--- a/apps/planner/app/components/ParticipantList.tsx
+++ /dev/null
@@ -1,136 +0,0 @@
-import { useEffect, useState, useRef, useCallback } from "react";
-import { useTranslation } from "react-i18next";
-import type { YjsState } from "~/lib/use-yjs";
-import { electHost } from "~/lib/host-election";
-
-interface Participant {
-  clientId: number;
-  name: string;
-  color: string;
-  isHost: boolean;
-  isLocal: boolean;
-}
-
-interface ParticipantListProps {
-  yjs: YjsState;
-}
-
-export function ParticipantList({ yjs }: ParticipantListProps) {
-  const { t } = useTranslation("planner");
-  const [participants, setParticipants] = useState<Participant[]>([]);
-  const [editing, setEditing] = useState(false);
-  const [editValue, setEditValue] = useState("");
-  const inputRef = useRef<HTMLInputElement>(null);
-
-  const updateParticipants = useCallback(() => {
-    const states = yjs.awareness.getStates() as Map<number, Record<string, unknown>>;
-    const localId = yjs.awareness.clientID;
-
-    const list: Participant[] = [];
-    states.forEach((state, clientId) => {
-      const user = state.user as { color: string; name: string } | undefined;
-      if (!user) return;
-
-      const { isHost } = electHost(states, clientId);
-
-      list.push({
-        clientId,
-        name: user.name,
-        color: user.color,
-        isHost,
-        isLocal: clientId === localId,
-      });
-    });
-
-    // Sort: local user first, then host, then alphabetical
-    list.sort((a, b) => {
-      if (a.isLocal !== b.isLocal) return a.isLocal ? -1 : 1;
-      if (a.isHost !== b.isHost) return a.isHost ? -1 : 1;
-      return a.name.localeCompare(b.name);
-    });
-
-    setParticipants(list);
-  }, [yjs.awareness]);
-
-  useEffect(() => {
-    yjs.awareness.on("change", updateParticipants);
-    updateParticipants();
-
-    return () => {
-      yjs.awareness.off("change", updateParticipants);
-    };
-  }, [yjs.awareness, updateParticipants]);
-
-  const startEditing = () => {
-    const localParticipant = participants.find((p) => p.isLocal);
-    if (localParticipant) {
-      setEditValue(localParticipant.name);
-      setEditing(true);
-    }
-  };
-
-  useEffect(() => {
-    if (editing && inputRef.current) {
-      inputRef.current.focus();
-      inputRef.current.select();
-    }
-  }, [editing]);
-
-  const commitEdit = () => {
-    const trimmed = editValue.trim();
-    if (trimmed && trimmed.length <= 20) {
-      yjs.setUserName(trimmed);
-    }
-    setEditing(false);
-  };
-
-  const handleKeyDown = (e: React.KeyboardEvent) => {
-    if (e.key === "Enter") {
-      commitEdit();
-    } else if (e.key === "Escape") {
-      setEditing(false);
-    }
-  };
-
-  return (
-    <div className="flex items-center gap-1.5">
-      {participants.map((p) => (
-        <div key={p.clientId} className="flex items-center gap-1">
-          <span
-            className="inline-block h-2.5 w-2.5 rounded-full flex-shrink-0"
-            style={{ backgroundColor: p.color }}
-          />
-          {p.isLocal && editing ? (
-            <input
-              ref={inputRef}
-              type="text"
-              value={editValue}
-              onChange={(e) => setEditValue(e.target.value)}
-              onBlur={commitEdit}
-              onKeyDown={handleKeyDown}
-              maxLength={20}
-              className="w-20 rounded border border-gray-300 px-1 py-0 text-base sm:text-xs text-gray-700 focus:border-blue-500 focus:outline-none"
-            />
-          ) : (
-            <button
-              type="button"
-              onClick={p.isLocal ? startEditing : undefined}
-              className={`text-xs text-gray-700 ${p.isLocal ? "cursor-pointer hover:underline" : "cursor-default"}`}
-              title={p.isLocal ? t("participants.editName") : p.name}
-            >
-              {p.name}
-              {p.isLocal && (
-                <span className="ml-0.5 text-gray-400">{t("participants.you")}</span>
-              )}
-            </button>
-          )}
-          {p.isHost && (
-            <span className="rounded-full bg-green-100 px-1.5 py-0 text-[10px] text-green-700">
-              {t("participants.host")}
-            </span>
-          )}
-        </div>
-      ))}
-    </div>
-  );
-}
diff --git a/apps/planner/app/components/SessionView.tsx b/apps/planner/app/components/SessionView.tsx
index 38650d4..a1b4a66 100644
--- a/apps/planner/app/components/SessionView.tsx
+++ b/apps/planner/app/components/SessionView.tsx
@@ -1,6 +1,5 @@
 import { Suspense, lazy, useState, useCallback, useEffect, useRef } from "react";
 import { useTranslation } from "react-i18next";
-import { Link } from "react-router";
 import L from "leaflet";
 import type { TFunction } from "i18next";
 import * as Sentry from "@sentry/react";
@@ -13,7 +12,8 @@ import { ProfileSelector } from "~/components/ProfileSelector";
 import { ExportButton } from "~/components/ExportButton";
 import { SaveToJournalButton } from "~/components/SaveToJournalButton";
 import { YjsDebugPanel } from "~/components/YjsDebugPanel";
-import { ParticipantList } from "~/components/ParticipantList";
+import { Topbar } from "~/components/Topbar";
+import { useParticipants } from "~/lib/use-participants";
 import { NotesPanel } from "~/components/NotesPanel";
 
 const PlannerMap = lazy(() =>
@@ -169,6 +169,7 @@ export function SessionView({ sessionId, hasJournalCallback, returnUrl, initialW
   const { computing, routeError, routeStats, requestRoute } = useRouting(yjs, sessionId);
   const { canUndo, canRedo, undo, redo } = useUndo(yjs?.undoManager ?? null);
   useUndoShortcuts(yjs?.undoManager ?? null);
+  const { participants, renameLocal } = useParticipants(yjs);
   const days = useDays(yjs);
   const [highlightPosition, setHighlightPosition] = useState<[number, number] | null>(null);
   const [highlightedWaypoint, setHighlightedWaypoint] = useState<number | null>(null);
@@ -226,51 +227,30 @@ export function SessionView({ sessionId, hasJournalCallback, returnUrl, initialW
 
   return (
     <>
-      <header className="flex items-center justify-between gap-2 border-b border-gray-200 px-3 py-1.5 pt-[max(0.375rem,env(safe-area-inset-top))] sm:px-4 sm:py-2">
-        <div className="flex items-center gap-1.5 sm:gap-4 min-w-0">
-          <Link to="/" className="hidden text-lg font-semibold text-gray-900 hover:text-blue-600 sm:block">
-            {t("title")}
-          </Link>
-          <ProfileSelector yjs={yjs} />
-          <div className="hidden sm:block">
-            <ParticipantList yjs={yjs} />
-          </div>
-          <div className="hidden sm:flex gap-1">
-            <button
-              onClick={undo}
-              disabled={!canUndo}
-              title={t("undo.tooltip")}
-              className="rounded px-1.5 py-1 text-gray-500 hover:bg-gray-100 disabled:opacity-30 disabled:hover:bg-transparent"
-            >
-              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round"><polyline points="1 4 1 10 7 10"/><path d="M3.51 15a9 9 0 1 0 2.13-9.36L1 10"/></svg>
-            </button>
-            <button
-              onClick={redo}
-              disabled={!canRedo}
-              title={t("redo.tooltip")}
-              className="rounded px-1.5 py-1 text-gray-500 hover:bg-gray-100 disabled:opacity-30 disabled:hover:bg-transparent"
-            >
-              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round"><polyline points="23 4 23 10 17 10"/><path d="M20.49 15a9 9 0 1 1-2.13-9.36L23 10"/></svg>
-            </button>
-          </div>
-        </div>
-        <div className="flex items-center gap-2 sm:gap-3 shrink-0">
-          {hasJournalCallback && (
-            <SaveToJournalButton
-              yjs={yjs}
-              sessionId={sessionId}
-              returnUrl={returnUrl}
-            />
-          )}
-          <ExportButton yjs={yjs} />
-          {computing && (
-            <span className="hidden text-xs text-blue-600 sm:inline">{t("computingRoute")}</span>
-          )}
-          <span className="hidden text-sm text-gray-500 sm:inline">
-            {yjs.connected ? t("connected") : t("connecting")} · {sessionId.slice(0, 8)}
-          </span>
-        </div>
-      </header>
+      <Topbar
+        participants={participants}
+        onRenameLocal={renameLocal}
+        connected={yjs.connected}
+        sessionShortId={sessionId.slice(0, 8)}
+        canUndo={canUndo}
+        canRedo={canRedo}
+        onUndo={undo}
+        onRedo={redo}
+        computing={computing}
+        profileSlot={<ProfileSelector yjs={yjs} />}
+        actions={
+          <>
+            {hasJournalCallback && (
+              <SaveToJournalButton
+                yjs={yjs}
+                sessionId={sessionId}
+                returnUrl={returnUrl}
+              />
+            )}
+            <ExportButton yjs={yjs} />
+          </>
+        }
+      />
       <div className="flex flex-1 overflow-hidden">
         <main className="flex-1 flex flex-col">
           <div className="relative flex-1">
diff --git a/apps/planner/app/components/Topbar.tsx b/apps/planner/app/components/Topbar.tsx
new file mode 100644
index 0000000..d61f48c
--- /dev/null
+++ b/apps/planner/app/components/Topbar.tsx
@@ -0,0 +1,104 @@
+import type { ReactNode } from "react";
+import { Link } from "react-router";
+import { useTranslation } from "react-i18next";
+import { IconButton } from "@trails-cool/ui";
+import { ParticipantAvatars } from "~/components/ParticipantAvatars";
+import type { Participant } from "~/lib/use-participants";
+
+interface TopbarProps {
+  participants: Participant[];
+  onRenameLocal?: (name: string) => void;
+  connected: boolean;
+  sessionShortId: string;
+  canUndo: boolean;
+  canRedo: boolean;
+  onUndo: () => void;
+  onRedo: () => void;
+  computing?: boolean;
+  /** App-specific interactive slot (profile selector). */
+  profileSlot?: ReactNode;
+  /** Right-aligned action slot (save-to-journal, export). */
+  actions?: ReactNode;
+}
+
+const UndoIcon = () => (
+  <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+    <polyline points="1 4 1 10 7 10" />
+    <path d="M3.51 15a9 9 0 1 0 2.13-9.36L1 10" />
+  </svg>
+);
+const RedoIcon = () => (
+  <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+    <polyline points="23 4 23 10 17 10" />
+    <path d="M20.49 15a9 9 0 1 1-2.13-9.36L23 10" />
+  </svg>
+);
+
+export function Topbar({
+  participants,
+  onRenameLocal,
+  connected,
+  sessionShortId,
+  canUndo,
+  canRedo,
+  onUndo,
+  onRedo,
+  computing = false,
+  profileSlot,
+  actions,
+}: TopbarProps) {
+  const { t } = useTranslation("planner");
+
+  return (
+    <header className="flex items-center justify-between gap-2 border-b border-border bg-bg-raised px-3 py-1.5 pt-[max(0.375rem,env(safe-area-inset-top))] sm:px-4 sm:py-2">
+      <div className="flex min-w-0 items-center gap-1.5 sm:gap-4">
+        <Link
+          to="/"
+          className="hidden shrink-0 text-lg font-semibold tracking-tight text-text-hi hover:text-accent sm:block"
+        >
+          {t("title")}
+        </Link>
+        <div className="shrink-0">{profileSlot}</div>
+        <div className="hidden min-w-0 overflow-hidden sm:block">
+          <ParticipantAvatars
+            participants={participants}
+            onRenameLocal={onRenameLocal}
+          />
+        </div>
+        <div className="hidden shrink-0 gap-0.5 sm:flex">
+          <IconButton
+            size="sm"
+            label={t("undo.tooltip")}
+            onClick={onUndo}
+            disabled={!canUndo}
+          >
+            <UndoIcon />
+          </IconButton>
+          <IconButton
+            size="sm"
+            label={t("redo.tooltip")}
+            onClick={onRedo}
+            disabled={!canRedo}
+          >
+            <RedoIcon />
+          </IconButton>
+        </div>
+      </div>
+      <div className="flex shrink-0 items-center gap-2 sm:gap-3">
+        {actions}
+        {computing && (
+          <span className="hidden text-xs text-accent sm:inline">
+            {t("computingRoute")}
+          </span>
+        )}
+        <span className="hidden items-center gap-1.5 text-sm text-text-md sm:inline-flex">
+          <span
+            className={`inline-block h-1.5 w-1.5 rounded-full ${connected ? "bg-accent" : "bg-text-lo"}`}
+            aria-hidden
+          />
+          {connected ? t("connected") : t("connecting")} · {sessionShortId}
+        </span>
+      </div>
+    </header>
+  );
+}
diff --git a/apps/planner/app/lib/use-participants.ts b/apps/planner/app/lib/use-participants.ts
new file mode 100644
index 0000000..f0737dc
--- /dev/null
+++ b/apps/planner/app/lib/use-participants.ts
@@ -0,0 +1,80 @@
+import { useCallback, useEffect, useState } from "react";
+import type { YjsState } from "./use-yjs";
+import { electHost } from "./host-election";
+
+export interface Participant {
+  clientId: number;
+  name: string;
+  color: string;
+  isHost: boolean;
+  isLocal: boolean;
+}
+
+/**
+ * Derive the live participant list from Yjs awareness, sorted local → host →
+ * alphabetical. Presentational components (ParticipantAvatars, the gallery)
+ * take the resulting plain array so they can be rendered without a live
+ * session. Accepts a null session so it can be called before SessionView's
+ * connecting-gate early return.
+ */
+export function useParticipants(yjs: YjsState | null): {
+  participants: Participant[];
+  renameLocal: (name: string) => void;
+} {
+  const [participants, setParticipants] = useState<Participant[]>([]);
+
+  const update = useCallback(() => {
+    if (!yjs) {
+      setParticipants([]);
+      return;
+    }
+    const states = yjs.awareness.getStates() as Map<
+      number,
+      Record<string, unknown>
+    >;
+    const localId = yjs.awareness.clientID;
+
+    const list: Participant[] = [];
+    states.forEach((state, clientId) => {
+      const user = state.user as { color: string; name: string } | undefined;
+      if (!user) return;
+      const { isHost } = electHost(states, clientId);
+      list.push({
+        clientId,
+        name: user.name,
+        color: user.color,
+        isHost,
+        isLocal: clientId === localId,
+      });
+    });
+
+    list.sort((a, b) => {
+      if (a.isLocal !== b.isLocal) return a.isLocal ? -1 : 1;
+      if (a.isHost !== b.isHost) return a.isHost ? -1 : 1;
+      return a.name.localeCompare(b.name);
+    });
+
+    setParticipants(list);
+  }, [yjs]);
+
+  useEffect(() => {
+    if (!yjs) return;
+    yjs.awareness.on("change", update);
+    update();
+    return () => {
+      yjs.awareness.off("change", update);
+    };
+  }, [yjs, update]);
+
+  const renameLocal = useCallback(
+    (name: string) => {
+      const trimmed = name.trim();
+      if (yjs && trimmed && trimmed.length <= 20) {
+        yjs.setUserName(trimmed);
+      }
+    },
+    [yjs],
+  );
+
+  return { participants, renameLocal };
+}
diff --git a/apps/planner/app/routes/dev.ui.tsx b/apps/planner/app/routes/dev.ui.tsx
index e463757..e662bf3 100644
--- a/apps/planner/app/routes/dev.ui.tsx
+++ b/apps/planner/app/routes/dev.ui.tsx
@@ -8,6 +8,40 @@ import {
   Input,
   SegmentedControl,
 } from "@trails-cool/ui";
+import { Topbar } from "~/components/Topbar";
+import type { Participant } from "~/lib/use-participants";
+
+const SOLO: Participant[] = [
+  { clientId: 1, name: "ulle", color: "#4A6B40", isHost: true, isLocal: true },
+];
+const PARTY: Participant[] = [
+  { clientId: 1, name: "ulle", color: "#4A6B40", isHost: true, isLocal: true },
+  { clientId: 2, name: "Mara", color: "#8B6D3A", isHost: false, isLocal: false },
+  { clientId: 3, name: "Sam", color: "#C46040", isHost: false, isLocal: false },
+];
+
+const noop = () => {};
+const profilePlaceholder = (
+  <Button variant="ghost" size="sm">
+    🚴 Cycling
+  </Button>
+);
+const actionsPlaceholder = (
+  <Button variant="secondary" size="sm">
+    Export GPX
+  </Button>
+);
+
+function TopbarConfig({ caption, children }: { caption: string; children: ReactNode }) {
+  return (
+    <div className="space-y-1.5">
+      <p className="text-xs text-text-md">{caption}</p>
+      <div className="overflow-hidden rounded-lg border border-border">
+        {children}
+      </div>
+    </div>
+  );
+}
 
 const UndoIcon = () => (
   <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
@@ -127,6 +161,52 @@ export default function DevUi() {
         </span>
       </Section>
 
+      <section className="space-y-4">
+        <h2 className="font-mono text-xs uppercase tracking-wider text-text-lo">
+          Topbar · configurations
+        </h2>
+        <TopbarConfig caption="Solo · connected · host">
+          <Topbar
+            participants={SOLO}
+            connected
+            sessionShortId="a83eddb4"
+            canUndo={false}
+            canRedo={false}
+            onUndo={noop}
+            onRedo={noop}
+            profileSlot={profilePlaceholder}
+            actions={actionsPlaceholder}
+          />
+        </TopbarConfig>
+        <TopbarConfig caption="Multiplayer · connected · computing route · undo available">
+          <Topbar
+            participants={PARTY}
+            connected
+            sessionShortId="a83eddb4"
+            canUndo
+            canRedo={false}
+            onUndo={noop}
+            onRedo={noop}
+            computing
+            profileSlot={profilePlaceholder}
+            actions={actionsPlaceholder}
+          />
+        </TopbarConfig>
+        <TopbarConfig caption="Guest · connecting (offline dot)">
+          <Topbar
+            participants={PARTY.slice(1)}
+            connected={false}
+            sessionShortId="a83eddb4"
+            canUndo={false}
+            canRedo={false}
+            onUndo={noop}
+            onRedo={noop}
+            profileSlot={profilePlaceholder}
+            actions={actionsPlaceholder}
+          />
+        </TopbarConfig>
+      </section>
+
       <Section title="Card">
         <Card className="w-64">
           <h3 className="font-medium text-text-hi">Subtle card</h3>