fix: apply custom UI font to full app interface

- Set document.body.style.fontFamily directly (belt-and-suspenders
  alongside the CSS variable) to ensure the font propagates
- Use var(--ui-font-family) in .app-container so the main app area
  respects the custom font (was hardcoded, blocking inheritance)
- Rename 'Custom Font' setting to 'Custom Terminal Font' for clarity

src/lib/components/ConfigSidebar.svelte

@@ -953,9 +953,9 @@
         </p>
       </div>
 
-      <!-- Custom Font -->
+      <!-- Custom Terminal Font -->
       <div class="mb-4">
-        <span class="block text-sm text-[var(--text-secondary)] mb-2">Custom Font</span>
+        <span class="block text-sm text-[var(--text-secondary)] mb-2">Custom Terminal Font</span>
         <div class="flex flex-col gap-2">
           <input
             type="text"

src/lib/stores/config.test.ts

@@ -1331,23 +1331,28 @@ describe("config store", () => {
     beforeEach(() => {
       document.getElementById("hikari-custom-ui-font")?.remove();
       document.documentElement.style.removeProperty("--ui-font-family");
+      document.body.style.removeProperty("font-family");
       readFileMock.mockReset();
     });
 
-    it("removes CSS variable when both path and family are null", async () => {
+    it("removes CSS variable and body font-family when both path and family are null", async () => {
       document.documentElement.style.setProperty("--ui-font-family", "'SomeFont', sans-serif");
+      document.body.style.setProperty("font-family", "'SomeFont', sans-serif");
       await applyCustomUiFont(null, null);
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe("");
+      expect(document.body.style.getPropertyValue("font-family")).toBe("");
     });
 
-    it("removes CSS variable when both path and family are empty strings", async () => {
+    it("removes CSS variable and body font-family when both path and family are empty strings", async () => {
       document.documentElement.style.setProperty("--ui-font-family", "'SomeFont', sans-serif");
+      document.body.style.setProperty("font-family", "'SomeFont', sans-serif");
       await applyCustomUiFont("", "");
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe("");
+      expect(document.body.style.getPropertyValue("font-family")).toBe("");
       expect(document.getElementById("hikari-custom-ui-font")).toBeNull();
     });
 
-    it("injects @import for a CSS stylesheet URL", async () => {
+    it("injects @import for a CSS stylesheet URL and applies font to body", async () => {
       await applyCustomUiFont("https://fonts.googleapis.com/css2?family=Inter", "Inter");
       const style = document.getElementById("hikari-custom-ui-font");
       expect(style).not.toBeNull();
@@ -1357,9 +1362,10 @@ describe("config store", () => {
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
         "'Inter', sans-serif"
       );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
     });
 
-    it("injects @font-face for a direct font file URL (.woff2)", async () => {
+    it("injects @font-face for a direct font file URL (.woff2) and applies font to body", async () => {
       await applyCustomUiFont("https://example.com/fonts/Inter.woff2", "Inter");
       const style = document.getElementById("hikari-custom-ui-font");
       expect(style).not.toBeNull();
@@ -1368,15 +1374,19 @@ describe("config store", () => {
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
         "'Inter', sans-serif"
       );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
     });
 
-    it("uses HikariCustomUiFont as fallback family for direct font URLs when family is empty", async () => {
+    it("uses HikariCustomUiFont as fallback family and applies it to body", async () => {
       await applyCustomUiFont("https://example.com/fonts/Inter.woff2", "");
       const style = document.getElementById("hikari-custom-ui-font");
       expect(style?.textContent).toContain("'HikariCustomUiFont'");
+      expect(document.body.style.getPropertyValue("font-family")).toBe(
+        '"HikariCustomUiFont", sans-serif'
+      );
     });
 
-    it("reads local file and embeds as data URL", async () => {
+    it("reads local file and embeds as data URL, applies font to body", async () => {
       const fakeData = new Uint8Array([104, 101, 108, 108, 111]);
       readFileMock.mockResolvedValueOnce(fakeData);
 
@@ -1388,13 +1398,17 @@ describe("config store", () => {
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
         "'Inter', sans-serif"
       );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
     });
 
-    it("sets CSS variable when only family is provided (no path)", async () => {
+    it("sets CSS variable and body font-family when only family is provided (no path)", async () => {
       await applyCustomUiFont("", "SystemUiFont");
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
         "'SystemUiFont', sans-serif"
       );
+      expect(document.body.style.getPropertyValue("font-family")).toBe(
+        '"SystemUiFont", sans-serif'
+      );
     });
 
     it("replaces a previously injected style element", async () => {
@@ -1415,6 +1429,7 @@ describe("config store", () => {
     beforeEach(() => {
       document.getElementById("hikari-custom-ui-font")?.remove();
       document.documentElement.style.removeProperty("--ui-font-family");
+      document.body.style.removeProperty("font-family");
       readFileMock.mockReset();
       invokeMock.mockResolvedValue(undefined);
     });
@@ -1435,13 +1450,16 @@ describe("config store", () => {
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe(
         "'Inter', sans-serif"
       );
+      expect(document.body.style.getPropertyValue("font-family")).toBe('"Inter", sans-serif');
     });
 
     it("clears UI font when called with nulls", async () => {
       document.documentElement.style.setProperty("--ui-font-family", "'SomeFont', sans-serif");
+      document.body.style.setProperty("font-family", "'SomeFont', sans-serif");
       await configStore.setCustomUiFont(null, null);
 
       expect(document.documentElement.style.getPropertyValue("--ui-font-family")).toBe("");
+      expect(document.body.style.getPropertyValue("font-family")).toBe("");
       expect(invokeMock).toHaveBeenCalledWith(
         "save_config",
         expect.objectContaining({

src/lib/stores/config.ts

@@ -404,16 +404,19 @@ export async function applyCustomUiFont(path: string | null, family: string | nu
 
   if (!trimmedPath && !trimmedFamily) {
     document.documentElement.style.removeProperty(cssVar);
+    document.body?.style.removeProperty("font-family");
     return;
   }
 
+  const effectiveFamily = trimmedFamily || fallbackFamily;
+
   if (trimmedPath) {
-    await applyFontFromSource(trimmedPath, trimmedFamily || fallbackFamily, styleId);
+    await applyFontFromSource(trimmedPath, effectiveFamily, styleId);
   }
 
-  if (trimmedFamily) {
-    document.documentElement.style.setProperty(cssVar, `'${trimmedFamily}', sans-serif`);
-  }
+  const fontValue = `'${effectiveFamily}', sans-serif`;
+  document.documentElement.style.setProperty(cssVar, fontValue);
+  document.body?.style.setProperty("font-family", fontValue);
 }
 
 export { MIN_FONT_SIZE, MAX_FONT_SIZE, DEFAULT_FONT_SIZE };

src/routes/+page.svelte

@@ -602,13 +602,15 @@
 
 <style>
   .app-container {
-    font-family:
+    font-family: var(
+      --ui-font-family,
       "Inter",
       -apple-system,
       BlinkMacSystemFont,
       "Segoe UI",
       Roboto,
-      sans-serif;
+      sans-serif
+    );
   }
 
   .character-panel {