diff --git a/ui/goose2/index.html b/ui/goose2/index.html
index de8ca95e..d75202b5 100644
--- a/ui/goose2/index.html
+++ b/ui/goose2/index.html
@@ -62,11 +62,6 @@
             getDefaultAccent(resolvedTheme);
           const foreground = getContrastColor(accent);
           const density = localStorage.getItem("goose-density") || "comfortable";
-          const spacingScale = {
-            compact: "0.75",
-            comfortable: "1",
-            spacious: "1.25",
-          };
 
           root.classList.add(resolvedTheme === "dark" ? "dark" : "light");
           root.style.colorScheme = resolvedTheme === "dark" ? "dark" : "light";
@@ -75,10 +70,9 @@
           root.style.setProperty("--color-brand", accent);
           root.style.setProperty("--color-brand-foreground", foreground);
           root.style.accentColor = accent;
-          root.style.setProperty(
-            "--density-spacing",
-            spacingScale[density] || spacingScale.comfortable,
-          );
+          if (density === "compact" || density === "spacious") {
+            root.dataset.density = density;
+          }
         } catch {
           // ThemeProvider applies the canonical theme state after React mounts.
         }
diff --git a/ui/goose2/src/features/settings/ui/__tests__/AppearanceSettings.test.tsx b/ui/goose2/src/features/settings/ui/__tests__/AppearanceSettings.test.tsx
new file mode 100644
index 00000000..398b3c10
--- /dev/null
+++ b/ui/goose2/src/features/settings/ui/__tests__/AppearanceSettings.test.tsx
@@ -0,0 +1,42 @@
+import { screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { beforeEach, describe, expect, it } from "vitest";
+
+import { ThemeProvider } from "@/shared/theme/ThemeProvider";
+import { renderWithProviders } from "@/test/render";
+import { AppearanceSettings } from "../AppearanceSettings";
+
+describe("AppearanceSettings", () => {
+  beforeEach(() => {
+    localStorage.clear();
+    document.documentElement.removeAttribute("data-density");
+    document.documentElement.style.removeProperty("--density-spacing");
+    document.documentElement.style.removeProperty("--spacing");
+  });
+
+  it("updates interface density from the appearance controls", async () => {
+    const user = userEvent.setup();
+
+    renderWithProviders(
+      <ThemeProvider>
+        <AppearanceSettings />
+      </ThemeProvider>,
+    );
+
+    const compact = screen.getByRole("radio", { name: "Compact" });
+
+    await user.click(compact);
+
+    await waitFor(() => {
+      expect(localStorage.getItem("goose-density")).toBe("compact");
+      expect(document.documentElement.dataset.density).toBe("compact");
+      expect(
+        document.documentElement.style.getPropertyValue("--density-spacing"),
+      ).toBe("");
+      expect(document.documentElement.style.getPropertyValue("--spacing")).toBe(
+        "",
+      );
+    });
+    expect(compact).toHaveAttribute("data-state", "on");
+  });
+});
diff --git a/ui/goose2/src/shared/styles/globals.css b/ui/goose2/src/shared/styles/globals.css
index fa5af0cc..caa4d215 100644
--- a/ui/goose2/src/shared/styles/globals.css
+++ b/ui/goose2/src/shared/styles/globals.css
@@ -254,6 +254,16 @@
   --density-spacing: 1;
 }
 
+[data-density="compact"] {
+  --density-spacing: 0.75;
+  --spacing: 0.1875rem;
+}
+
+[data-density="spacious"] {
+  --density-spacing: 1.25;
+  --spacing: 0.3125rem;
+}
+
 .dark {
   /* theming accents */
   --brand: var(--color-white);
diff --git a/ui/goose2/src/shared/theme/ThemeProvider.test.tsx b/ui/goose2/src/shared/theme/ThemeProvider.test.tsx
index c0d1cbda..d1cb8cec 100644
--- a/ui/goose2/src/shared/theme/ThemeProvider.test.tsx
+++ b/ui/goose2/src/shared/theme/ThemeProvider.test.tsx
@@ -1,8 +1,19 @@
 import { render, screen } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
+import { readFileSync } from "node:fs";
+import { dirname, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
 import { describe, it, expect, beforeEach } from "vitest";
 import { ThemeProvider, useTheme } from "./ThemeProvider";
 
+const testDirname = dirname(fileURLToPath(import.meta.url));
+
+function rootCssVariable(name: string) {
+  return getComputedStyle(document.documentElement)
+    .getPropertyValue(name)
+    .trim();
+}
+
 function ThemeConsumer() {
   const {
     theme,
@@ -12,6 +23,7 @@ function ThemeConsumer() {
     setAccentColor,
     resetAccentColor,
     density,
+    setDensity,
   } = useTheme();
   return (
     <div>
@@ -37,6 +49,9 @@ function ThemeConsumer() {
       <button type="button" onClick={resetAccentColor}>
         Reset Accent
       </button>
+      <button type="button" onClick={() => setDensity("spacious")}>
+        Set Spacious
+      </button>
     </div>
   );
 }
@@ -45,6 +60,7 @@ describe("ThemeProvider", () => {
   beforeEach(() => {
     localStorage.clear();
     document.documentElement.classList.remove("light", "dark");
+    document.documentElement.removeAttribute("data-density");
     document.documentElement.removeAttribute("style");
   });
 
@@ -195,6 +211,23 @@ describe("ThemeProvider", () => {
     ).toBe("#000000");
   });
 
+  it("falls back to default accent color when storage is invalid", () => {
+    localStorage.setItem("goose-accent-color", "blue");
+
+    render(
+      <ThemeProvider>
+        <ThemeConsumer />
+      </ThemeProvider>,
+    );
+
+    expect(screen.getByTestId("accent")).toHaveTextContent("#1a1a1a");
+    expect(screen.getByTestId("accent-preference")).toHaveTextContent(
+      "default",
+    );
+    expect(rootCssVariable("--color-brand")).toBe("#1a1a1a");
+    expect(rootCssVariable("--color-brand-foreground")).toBe("#ffffff");
+  });
+
   it("provides default density", () => {
     render(
       <ThemeProvider>
@@ -202,5 +235,92 @@ describe("ThemeProvider", () => {
       </ThemeProvider>,
     );
     expect(screen.getByTestId("density")).toHaveTextContent("comfortable");
+    expect(document.documentElement).not.toHaveAttribute("data-density");
+    expect(
+      document.documentElement.style.getPropertyValue("--density-spacing"),
+    ).toBe("");
+    expect(document.documentElement.style.getPropertyValue("--spacing")).toBe(
+      "",
+    );
+  });
+
+  it("falls back to default theme when storage is invalid", () => {
+    localStorage.setItem("goose-theme", "sepia");
+
+    render(
+      <ThemeProvider>
+        <ThemeConsumer />
+      </ThemeProvider>,
+    );
+
+    expect(screen.getByTestId("theme")).toHaveTextContent("system");
+  });
+
+  it("reads persisted density", () => {
+    localStorage.setItem("goose-density", "compact");
+
+    render(
+      <ThemeProvider>
+        <ThemeConsumer />
+      </ThemeProvider>,
+    );
+
+    expect(screen.getByTestId("density")).toHaveTextContent("compact");
+    expect(document.documentElement.dataset.density).toBe("compact");
+    expect(
+      document.documentElement.style.getPropertyValue("--density-spacing"),
+    ).toBe("");
+    expect(document.documentElement.style.getPropertyValue("--spacing")).toBe(
+      "",
+    );
+  });
+
+  it("persists density and updates spacing tokens", async () => {
+    const user = userEvent.setup();
+    render(
+      <ThemeProvider>
+        <ThemeConsumer />
+      </ThemeProvider>,
+    );
+
+    await user.click(screen.getByText("Set Spacious"));
+
+    expect(screen.getByTestId("density")).toHaveTextContent("spacious");
+    expect(localStorage.getItem("goose-density")).toBe("spacious");
+    expect(document.documentElement.dataset.density).toBe("spacious");
+    expect(
+      document.documentElement.style.getPropertyValue("--density-spacing"),
+    ).toBe("");
+    expect(document.documentElement.style.getPropertyValue("--spacing")).toBe(
+      "",
+    );
+  });
+
+  it("falls back to comfortable density when storage is invalid", () => {
+    localStorage.setItem("goose-density", "tiny");
+
+    render(
+      <ThemeProvider>
+        <ThemeConsumer />
+      </ThemeProvider>,
+    );
+
+    expect(screen.getByTestId("density")).toHaveTextContent("comfortable");
+    expect(document.documentElement).not.toHaveAttribute("data-density");
+  });
+
+  it("keeps density spacing values in CSS", () => {
+    const css = readFileSync(
+      resolve(testDirname, "../styles/globals.css"),
+      "utf8",
+    );
+
+    expect(css).toContain('[data-density="compact"]');
+    expect(css).toContain("--density-spacing: 0.75;");
+    expect(css).toContain("--spacing: 0.1875rem;");
+    expect(css).toContain('[data-density="spacious"]');
+    expect(css).toContain("--density-spacing: 1.25;");
+    expect(css).toContain("--spacing: 0.3125rem;");
+    expect(css).toContain("padding: calc(0.5rem * var(--density-spacing));");
   });
 });
diff --git a/ui/goose2/src/shared/theme/ThemeProvider.tsx b/ui/goose2/src/shared/theme/ThemeProvider.tsx
index 690c71f8..c81a8a35 100644
--- a/ui/goose2/src/shared/theme/ThemeProvider.tsx
+++ b/ui/goose2/src/shared/theme/ThemeProvider.tsx
@@ -4,6 +4,9 @@ type ThemePreference = "light" | "dark" | "system";
 type ResolvedTheme = "light" | "dark";
 type Density = "compact" | "comfortable" | "spacious";
 
+const THEME_PREFERENCES = ["light", "dark", "system"] as const;
+const DENSITIES = ["compact", "comfortable", "spacious"] as const;
+
 type ThemeProviderProps = {
   children: React.ReactNode;
   defaultTheme?: ThemePreference;
@@ -29,6 +32,14 @@ const DEFAULT_ACCENT_COLOR_PREFERENCE = "default";
 const DEFAULT_LIGHT_ACCENT_COLOR = "#1a1a1a";
 const DEFAULT_DARK_ACCENT_COLOR = "#ffffff";
 
+function isDensity(value: string | null): value is Density {
+  return DENSITIES.includes(value as Density);
+}
+
+function isThemePreference(value: string | null): value is ThemePreference {
+  return THEME_PREFERENCES.includes(value as ThemePreference);
+}
+
 function resolveTheme(preference: ThemePreference): ResolvedTheme {
   if (preference === "system") {
     return window.matchMedia("(prefers-color-scheme: dark)").matches
@@ -93,15 +104,21 @@ function applyAccentColor(root: HTMLElement, color: string) {
   root.style.accentColor = color;
 }
 
+function applyDensityAttribute(root: HTMLElement, density: Density) {
+  if (density === "comfortable") {
+    root.removeAttribute("data-density");
+  } else {
+    root.dataset.density = density;
+  }
+}
+
 export function ThemeProvider({
   children,
   defaultTheme = "system",
 }: ThemeProviderProps) {
   const [theme, setThemeState] = React.useState<ThemePreference>(() => {
-    const stored = localStorage.getItem(
-      "goose-theme",
-    ) as ThemePreference | null;
-    return stored ?? defaultTheme;
+    const stored = localStorage.getItem("goose-theme");
+    return isThemePreference(stored) ? stored : defaultTheme;
   });
 
   const [resolvedTheme, setResolvedTheme] = React.useState<ResolvedTheme>(() =>
@@ -117,8 +134,8 @@ export function ThemeProvider({
     });
 
   const [density, setDensityState] = React.useState<Density>(() => {
-    const stored = localStorage.getItem("goose-density") as Density | null;
-    return stored ?? "comfortable";
+    const stored = localStorage.getItem("goose-density");
+    return isDensity(stored) ? stored : "comfortable";
   });
 
   const accentColor = React.useMemo(() => {
@@ -178,18 +195,11 @@ export function ThemeProvider({
   }, [theme]);
 
   React.useEffect(() => {
-    const root = window.document.documentElement;
-    applyAccentColor(root, accentColor);
+    applyAccentColor(window.document.documentElement, accentColor);
   }, [accentColor]);
 
-  React.useEffect(() => {
-    const root = window.document.documentElement;
-    const spacingScale: Record<Density, string> = {
-      compact: "0.75",
-      comfortable: "1",
-      spacious: "1.25",
-    };
-    root.style.setProperty("--density-spacing", spacingScale[density]);
+  React.useLayoutEffect(() => {
+    applyDensityAttribute(window.document.documentElement, density);
   }, [density]);
 
   const value = React.useMemo(