diff --git a/changelog.d/20261028-split-update-actions.md b/changelog.d/20261028-split-update-actions.md
new file mode 100644
index 0000000..c3a14f6
--- /dev/null
+++ b/changelog.d/20261028-split-update-actions.md
@@ -0,0 +1,7 @@
+---
+area: manager
+type: changed
+audience: admins
+title: Update and launch without updating share a divided button
+---
+Server and game client actions each use two adjacent segments of equal height. Both actions remain visible and keep their own availability checks.
diff --git a/changelog.d/20261028-window-density.md b/changelog.d/20261028-window-density.md
new file mode 100644
index 0000000..e987242
--- /dev/null
+++ b/changelog.d/20261028-window-density.md
@@ -0,0 +1,7 @@
+---
+area: manager
+type: fixed
+audience: admins
+title: Maximizing the window keeps text and controls at a comfortable size
+---
+The interface no longer enlarges with window width. System display scaling and browser zoom still work, and large action buttons use more compact spacing.
diff --git a/src/components/ui/button.tsx b/src/components/ui/button.tsx
index c9280ed..8511595 100644
--- a/src/components/ui/button.tsx
+++ b/src/components/ui/button.tsx
@@ -15,7 +15,7 @@ const buttonVariants = cva(
       size: {
         sm: "h-9 px-3 text-sm",
         md: "h-11 px-5 text-[15px]",
-        xl: "h-16 px-10 text-lg tracking-wide",
+        xl: "h-12 px-6 text-base",
       },
     },
     defaultVariants: { variant: "secondary", size: "md" },
diff --git a/src/components/ui/split-button.tsx b/src/components/ui/split-button.tsx
new file mode 100644
index 0000000..023bd2e
--- /dev/null
+++ b/src/components/ui/split-button.tsx
@@ -0,0 +1,15 @@
+import { Button, type ButtonProps } from "./button";
+
+/** Two explicit actions, each with its own enabled state and keyboard focus. */
+export function SplitButton({ label, primary, secondary }: {
+  label: string;
+  primary: ButtonProps;
+  secondary: ButtonProps;
+}) {
+  return <div role="group" aria-label={label} className="inline-flex max-w-full items-stretch rounded-md">
+    <Button type="button" variant="primary" {...primary}
+      className="h-auto min-h-12 min-w-0 rounded-r-none px-5 py-2 text-sm whitespace-normal" />
+    <Button type="button" variant="secondary" {...secondary}
+      className="h-auto min-h-12 min-w-0 rounded-l-none border-l border-l-gold/30 px-4 py-2 text-sm whitespace-normal" />
+  </div>;
+}
diff --git a/src/index.css b/src/index.css
index 13ef63c..8b4150b 100644
--- a/src/index.css
+++ b/src/index.css
@@ -16,10 +16,10 @@
   --font-sans: "Segoe UI Variable Text", "Segoe UI", "Microsoft YaHei UI", "Microsoft YaHei", system-ui, sans-serif;
 }
 
-/* Everything is sized in rem, so scaling the root font grows the whole interface with the window
-   (16px up to about 1280px wide, then gradually larger; capped at 26px). */
+/* Window size changes layout, not UI density. Keep rem tied to the user's default
+   font size; browser zoom and operating-system display scaling still apply. */
 html {
-  font-size: clamp(16px, calc(0.75vw + 6.4px), 26px);
+  font-size: 100%;
 }
 
 html,
diff --git a/src/screens/Overview.tsx b/src/screens/Overview.tsx
index f1b6057..5185592 100644
--- a/src/screens/Overview.tsx
+++ b/src/screens/Overview.tsx
@@ -15,6 +15,7 @@ import { PublishRealmDialog } from "@/screens/PublishDialog";
 import { useRegistryStatus } from "@/lib/registry";
 import { usePublishRealms, type PublishRealm } from "@/lib/publishRealms";
 import { useAutoRestart } from "@/lib/autoRestartPrefs";
+import { SplitButton } from "@/components/ui/split-button";
 import { Button } from "@/components/ui/button";
 import { Card } from "@/components/ui/card";
 
@@ -410,32 +411,21 @@ export function Overview({ server, companions = true, onForget, onOpenUpdates, o
 
         <div className="mt-7 flex flex-wrap items-center gap-x-4 gap-y-3">
           {running ? (
-            <Button variant="secondary" size="xl" disabled={transitioning} onClick={() => run("stopping")} className="min-w-56">
+            <Button variant="secondary" size="xl" disabled={transitioning} onClick={() => run("stopping")} className="min-w-40">
               {transitioning && <Loader2 className="h-5 w-5 animate-spin" aria-hidden />}
               {t("btn.stop")}
             </Button>
           ) : upd.available ? (
-            <Button
-              variant="primary"
-              size="xl"
-              disabled={transitioning || upd.applying}
-              onClick={() => (needsDecision ? onOpenUpdates() : void runServerUpdate())}
-              className="min-w-56"
-            >
-              {upd.applying && <Loader2 className="h-5 w-5 animate-spin" aria-hidden />}
-              {upd.applying ? t("btn.updating") : needsDecision ? t("overview.openUpdates") : t("btn.update")}
-            </Button>
+            <SplitButton label={t("overview.server")}
+              primary={{ disabled: transitioning || upd.applying, onClick: () => (needsDecision ? onOpenUpdates() : void runServerUpdate()), children: <>{upd.applying && <Loader2 className="h-4 w-4 animate-spin" aria-hidden />}{upd.applying ? t("btn.updating") : needsDecision ? t("overview.openUpdates") : t("btn.update")}</> }}
+              secondary={{ disabled: transitioning || upd.applying, onClick: () => run("starting"), children: t("btn.startWithoutUpdate") }}
+            />
           ) : (
-            <Button variant="primary" size="xl" disabled={transitioning} onClick={() => run("starting")} className="min-w-56">
+            <Button variant="primary" size="xl" disabled={transitioning} onClick={() => run("starting")} className="min-w-40">
               {transitioning && <Loader2 className="h-5 w-5 animate-spin" aria-hidden />}
               {transitioning ? (action === "stopping" ? t("btn.stoppingCaps") : t("btn.startingCaps")) : t("btn.start")}
             </Button>
           )}
-          {!running && upd.available && (
-            <Button variant="secondary" size="sm" disabled={transitioning || upd.applying} onClick={() => run("starting")}>
-              {t("btn.startWithoutUpdate")}
-            </Button>
-          )}
           {running && (
             <Button variant="ghost" size="sm" disabled={transitioning || upd.applying} onClick={() => run("restarting")}>
               {t("btn.restart")}
@@ -456,7 +446,7 @@ export function Overview({ server, companions = true, onForget, onOpenUpdates, o
           {client && <RealmlistMenu serverId={server.id} />}
           {client && jobBusy ? (
             <div
-              className="relative flex h-16 min-w-64 items-center overflow-hidden rounded-md border border-gold/50 bg-card-2"
+              className="relative flex h-12 min-w-64 items-center overflow-hidden rounded-md border border-gold/50 bg-card-2"
               role="progressbar"
               aria-valuenow={jobPct}
               aria-valuemin={0}
@@ -482,9 +472,10 @@ export function Overview({ server, companions = true, onForget, onOpenUpdates, o
               </button>
             </div>
           ) : client && (clientStatus?.update_available || job.phase === "choose") ? (
-            <Button variant="primary" size="xl" disabled={playing || job.phase === "choose"} onClick={() => void startClientUpdate(server.id)} className="min-w-40">
-              {t("btn.updateClient")}
-            </Button>
+            <SplitButton label={t("btn.play")}
+              primary={{ disabled: playing || job.phase === "choose", onClick: () => void startClientUpdate(server.id), children: t("btn.updateClient") }}
+              secondary={{ disabled: realmBusy || playing || upd.applying, onClick: () => void play(), children: <>{playing && <Loader2 className="h-4 w-4 animate-spin" aria-hidden />}{t("btn.playWithoutUpdate")}</> }}
+            />
           ) : client ? (
             <Button variant="primary" size="xl" disabled={realmBusy || playing} onClick={() => void play()} className="min-w-40">
               {playing && <Loader2 className="h-5 w-5 animate-spin" aria-hidden />}
@@ -495,11 +486,6 @@ export function Overview({ server, companions = true, onForget, onOpenUpdates, o
               {t("btn.setupClient")}
             </Button>
           ) : null}
-          {client && !jobBusy && (clientStatus?.update_available || job.phase === "choose") && (
-            <Button variant="secondary" size="sm" disabled={realmBusy || playing || upd.applying} onClick={() => void play()}>
-              {t("btn.playWithoutUpdate")}
-            </Button>
-          )}
           </div>
         </div>
         <div className="mt-6 flex flex-wrap items-center justify-between gap-3 border-t border-line/60 pt-4 text-xs text-muted">
diff --git a/src/screens/RealmlistMenu.tsx b/src/screens/RealmlistMenu.tsx
index b230f94..faf8530 100644
--- a/src/screens/RealmlistMenu.tsx
+++ b/src/screens/RealmlistMenu.tsx
@@ -92,7 +92,7 @@ export function RealmlistMenu({ serverId, className }: { serverId: string; class
         onClick={() => setOpen((v) => !v)}
         aria-haspopup="menu"
         aria-expanded={open}
-        className="flex h-16 cursor-pointer items-center gap-3 rounded-md border border-line bg-card-2 px-4 text-left transition-colors hover:border-gold/50"
+        className="flex h-12 cursor-pointer items-center gap-3 rounded-md border border-line bg-card-2 px-4 text-left transition-colors hover:border-gold/50"
       >
         <span>
           <span className="block text-[11px] uppercase tracking-wide text-muted">{t("realm.label")}</span>
diff --git a/tools/overview-update-error.test.mjs b/tools/overview-update-error.test.mjs
index d5d52d0..eabc282 100644
--- a/tools/overview-update-error.test.mjs
+++ b/tools/overview-update-error.test.mjs
@@ -28,6 +28,7 @@ const bundle = await rolldown({
   external: (id, importer) => id === "react/jsx-runtime" || id === "lucide-react" || (id === "react" && !importer?.endsWith("Overview.tsx")),
   plugins: [{ name: "overview-test",
     resolveId(id, importer) {
+      if (id === "@/components/ui/split-button") return fileURLToPath(new URL("../src/components/ui/split-button.tsx", import.meta.url));
       if (id.startsWith("@/") || (id === "react" && importer?.endsWith("Overview.tsx"))) return "\0" + id;
     },
     load(id) {