diff --git a/apps/web/src/components/GitActionsControl.tsx b/apps/web/src/components/GitActionsControl.tsx
index f816f60b402688bcc8f2c1af0073618ff2e8de9d..aa3767a3155abe05d3da78663347eb4b24064b07 100644
--- a/apps/web/src/components/GitActionsControl.tsx
+++ b/apps/web/src/components/GitActionsControl.tsx
@@ -1878,9 +1878,9 @@ export default function GitActionsControl({
                                     <span className="text-muted-foreground">Excluded</span>
                                   ) : (
                                     <>
-                                      <span className="text-success">+{file.insertions}</span>
+                                      <span className="text-diff-addition">+{file.insertions}</span>
                                       <span className="text-muted-foreground"> / </span>
-                                      <span className="text-destructive">-{file.deletions}</span>
+                                      <span className="text-diff-deletion">-{file.deletions}</span>
                                     </>
                                   )}
                                 </span>
@@ -1891,11 +1891,11 @@ export default function GitActionsControl({
                       </div>
                     </ScrollArea>
                     <div className="flex justify-end font-mono">
-                      <span className="text-success">
+                      <span className="text-diff-addition">
                         +{selectedFiles.reduce((sum, f) => sum + f.insertions, 0)}
                       </span>
                       <span className="text-muted-foreground"> / </span>
-                      <span className="text-destructive">
+                      <span className="text-diff-deletion">
                         -{selectedFiles.reduce((sum, f) => sum + f.deletions, 0)}
                       </span>
                     </div>
diff --git a/apps/web/src/components/Sidebar.tsx b/apps/web/src/components/Sidebar.tsx
index 78c59e296b90a85e5d98a21d5f29ba02526479e6..79573635212ec5ee4591900e90283c9e1fd53c20 100644
--- a/apps/web/src/components/Sidebar.tsx
+++ b/apps/web/src/components/Sidebar.tsx
@@ -1932,8 +1932,8 @@ const SidebarThreadRow = memo(function SidebarThreadRow(props: {
               ) : null}
               {diff ? (
                 <span className="shrink-0 font-mono">
-                  <span className="text-emerald-600 dark:text-emerald-400">+{diff.insertions}</span>{" "}
-                  <span className="text-red-600 dark:text-red-400">−{diff.deletions}</span>
+                  <span className="text-diff-addition-foreground">+{diff.insertions}</span>{" "}
+                  <span className="text-diff-deletion-foreground">−{diff.deletions}</span>
                 </span>
               ) : null}
               <span
diff --git a/apps/web/src/components/chat/DiffStatLabel.tsx b/apps/web/src/components/chat/DiffStatLabel.tsx
index 6787a8df1963bd75daa53399a9208db17bfc562d..a4110afe8a235f8fd2ffa500db90f38f58328cbc 100644
--- a/apps/web/src/components/chat/DiffStatLabel.tsx
+++ b/apps/web/src/components/chat/DiffStatLabel.tsx
@@ -40,10 +40,10 @@ export const DiffStatLabel = memo(function DiffStatLabel(props: {
           className,
         )}
       >
-        <span aria-hidden="true" className="font-mono text-success">
+        <span aria-hidden="true" className="font-mono text-diff-addition">
           +{formatCompactDiffCount(additions)}
         </span>
-        <span aria-hidden="true" className="font-mono text-destructive">
+        <span aria-hidden="true" className="font-mono text-diff-deletion">
           -{formatCompactDiffCount(deletions)}
         </span>
       </span>
diff --git a/apps/web/src/components/pullRequest/pullRequestPresentation.tsx b/apps/web/src/components/pullRequest/pullRequestPresentation.tsx
index 3c41e0956fedf348b17736ecf3719e61b1336fbb..9cd3340832ddfe2ccf36209f5ffdc9e7f8260892 100644
--- a/apps/web/src/components/pullRequest/pullRequestPresentation.tsx
+++ b/apps/web/src/components/pullRequest/pullRequestPresentation.tsx
@@ -422,10 +422,8 @@ export function PullRequestDiffStat({
   }
   return (
     <span className={cn("inline-flex items-baseline gap-1 tabular-nums", className)}>
-      <span className="text-emerald-600 dark:text-emerald-300/90">
-        +{additions.toLocaleString()}
-      </span>
-      <span className="text-destructive">-{deletions.toLocaleString()}</span>
+      <span className="text-diff-addition-foreground">+{additions.toLocaleString()}</span>
+      <span className="text-diff-deletion">-{deletions.toLocaleString()}</span>
     </span>
   );
 }
diff --git a/apps/web/src/components/settings/SettingsPanels.tsx b/apps/web/src/components/settings/SettingsPanels.tsx
index 4c108b01d0c8c3487bcbc993b38b0850aa5145dc..143680509544907a6443bde6762ce2c98b4ed1fb 100644
--- a/apps/web/src/components/settings/SettingsPanels.tsx
+++ b/apps/web/src/components/settings/SettingsPanels.tsx
@@ -506,6 +506,9 @@ export function useSettingsRestore(onRestored?: () => void) {
         ? ["Contrast"]
         : []),
       ...(settings.glassOpacity !== DEFAULT_UNIFIED_SETTINGS.glassOpacity ? ["Glass opacity"] : []),
+      ...(settings.diffColorScheme !== DEFAULT_UNIFIED_SETTINGS.diffColorScheme
+        ? ["Diff colors"]
+        : []),
       ...(settings.panelAnimationDurationMs !== DEFAULT_UNIFIED_SETTINGS.panelAnimationDurationMs
         ? ["Panel animations"]
         : []),
@@ -597,6 +600,7 @@ export function useSettingsRestore(onRestored?: () => void) {
       settings.browserLinkTarget,
       settings.browserAutoShowFloatingPreview,
       settings.appearanceContrast,
+      settings.diffColorScheme,
       settings.enableAgentBrowserAccess,
       settings.confirmQuit,
       settings.confirmThreadArchive,
@@ -701,6 +705,7 @@ export function useSettingsRestore(onRestored?: () => void) {
     }
     updateSettings({
       appearanceContrast: DEFAULT_UNIFIED_SETTINGS.appearanceContrast,
+      diffColorScheme: DEFAULT_UNIFIED_SETTINGS.diffColorScheme,
       timestampFormat: DEFAULT_UNIFIED_SETTINGS.timestampFormat,
       wordWrap: DEFAULT_UNIFIED_SETTINGS.wordWrap,
       diffIgnoreWhitespace: DEFAULT_UNIFIED_SETTINGS.diffIgnoreWhitespace,
@@ -1240,6 +1245,52 @@ export function AppearanceSettingsPanel() {
             }
           />
         ) : null}
+        <SettingsRow
+          {...searchableSetting("diff-color-scheme")}
+          description="Choose colors for additions and deletions, including change counts."
+          resetAction={
+            settings.diffColorScheme !== DEFAULT_UNIFIED_SETTINGS.diffColorScheme ? (
+              <SettingResetButton
+                label="diff colors"
+                onClick={() =>
+                  updateSettings({ diffColorScheme: DEFAULT_UNIFIED_SETTINGS.diffColorScheme })
+                }
+              />
+            ) : null
+          }
+          control={
+            <div className="w-full sm:w-40">
+              <Select
+                value={settings.diffColorScheme}
+                onValueChange={(value) => {
+                  if (value === "red-green" || value === "blue-orange")
+                    updateSettings({ diffColorScheme: value });
+                }}
+              >
+                <SelectTrigger size="sm" className="w-full min-w-0" aria-label="Diff colors">
+                  <span
+                    aria-hidden="true"
+                    className={
+                      settings.diffColorScheme === "blue-orange"
+                        ? "flex shrink-0 flex-row-reverse gap-1"
+                        : "flex shrink-0 gap-1"
+                    }
+                  >
+                    <span className="size-2 rounded-full bg-[var(--diff-deletion)]" />
+                    <span className="size-2 rounded-full bg-[var(--diff-addition)]" />
+                  </span>
+                  <SelectValue>
+                    {settings.diffColorScheme === "blue-orange" ? "Blue & orange" : "Red & green"}
+                  </SelectValue>
+                </SelectTrigger>
+                <SelectPopup align="end" alignItemWithTrigger={false}>
+                  <SelectItem value="red-green">Red & green (default)</SelectItem>
+                  <SelectItem value="blue-orange">Blue & orange</SelectItem>
+                </SelectPopup>
+              </Select>
+            </div>
+          }
+        />
       </SettingsSection>
 
       <SettingsSection id="motion" title="Motion">
diff --git a/apps/web/src/components/settings/settingsSearch.ts b/apps/web/src/components/settings/settingsSearch.ts
index e32baf6f39874b3f34fc0ecc26558e58dd18a0b8..5cf35a54339257d81397b4114efb1ee8904c110d 100644
--- a/apps/web/src/components/settings/settingsSearch.ts
+++ b/apps/web/src/components/settings/settingsSearch.ts
@@ -106,6 +106,12 @@ export const SETTINGS_SEARCH_ITEMS = [
     to: "/settings/appearance",
     searchTerms: ["transparent transparency solid menus dialogs composer"],
   },
+  {
+    id: "diff-color-scheme",
+    title: "Diff colors",
+    to: "/settings/appearance",
+    searchTerms: ["red green blue orange additions deletions changes counts palette colorblind"],
+  },
   {
     id: "panel-animations",
     title: "Panel animations",
diff --git a/apps/web/src/index.css b/apps/web/src/index.css
index 1d7975d24677f0e52977522f9924f382e0d398d5..f7f669b804fded8684cba07f4d0c6fe60499e2e4 100644
--- a/apps/web/src/index.css
+++ b/apps/web/src/index.css
@@ -162,6 +162,10 @@ html[data-mobile-composer-route-transition="true"]::view-transition-old(t3-mobil
   --color-update-surface: var(--update-surface);
   --color-success-foreground: var(--success-foreground);
   --color-success: var(--success);
+  --color-diff-addition: var(--diff-addition);
+  --color-diff-deletion: var(--diff-deletion);
+  --color-diff-addition-foreground: var(--diff-addition-foreground);
+  --color-diff-deletion-foreground: var(--diff-deletion-foreground);
   --color-info-foreground: var(--info-foreground);
   --color-info: var(--info);
   --color-destructive-foreground: var(--destructive-foreground);
@@ -1955,6 +1959,28 @@ code {
   }
 }
 
+:root {
+  --diff-addition: var(--success);
+  --diff-deletion: var(--destructive);
+  --diff-addition-foreground: light-dark(var(--color-emerald-600), var(--color-emerald-400));
+  --diff-deletion-foreground: light-dark(var(--color-red-600), var(--color-red-400));
+}
+
+:root[data-diff-color-scheme="blue-orange"] {
+  --diff-addition: light-dark(var(--color-blue-600), var(--color-blue-400));
+  --diff-deletion: light-dark(var(--color-orange-600), var(--color-orange-400));
+  --diff-addition-foreground: var(--diff-addition);
+  --diff-deletion-foreground: var(--diff-deletion);
+  --diffs-addition-color-override: var(--diff-addition);
+  --diffs-deletion-color-override: var(--diff-deletion);
+  --trees-status-added-override: var(--diff-addition);
+  --trees-status-deleted-override: var(--diff-deletion);
+  --trees-status-untracked-override: var(--diff-addition);
+  --trees-git-added-color-override: var(--diff-addition);
+  --trees-git-deleted-color-override: var(--diff-deletion);
+  --trees-git-untracked-color-override: var(--diff-addition);
+}
+
 .diff-render-surface diffs-container {
   border: 0;
   border-radius: 0;
diff --git a/apps/web/src/lib/diffRendering.ts b/apps/web/src/lib/diffRendering.ts
index 2866e88f45f68b99f247051157d6e48e27cf49a8..90c456aa9da127a6cf5cb9976c2c90dc5fbcd2ce 100644
--- a/apps/web/src/lib/diffRendering.ts
+++ b/apps/web/src/lib/diffRendering.ts
@@ -282,37 +282,37 @@ export const DIFF_SURFACE_THEME_UNSAFE_CSS = `
   --diffs-bg-buffer-override: color-mix(in srgb, var(--code-background) 90%, var(--code-foreground));
 
   --diffs-bg-addition-override: light-dark(
-    color-mix(in srgb, var(--code-background) 50%, var(--success)),
-    color-mix(in srgb, var(--code-background) 70%, var(--success))
+    color-mix(in srgb, var(--code-background) 50%, var(--diff-addition)),
+    color-mix(in srgb, var(--code-background) 70%, var(--diff-addition))
   );
   --diffs-bg-addition-number-override: light-dark(
-    color-mix(in srgb, var(--code-background) 35%, var(--success)),
-    color-mix(in srgb, var(--code-background) 60%, var(--success))
+    color-mix(in srgb, var(--code-background) 35%, var(--diff-addition)),
+    color-mix(in srgb, var(--code-background) 60%, var(--diff-addition))
   );
-  --diffs-bg-addition-hover-override: color-mix(in srgb, var(--code-background) 85%, var(--success));
+  --diffs-bg-addition-hover-override: color-mix(in srgb, var(--code-background) 85%, var(--diff-addition));
   --diffs-bg-addition-emphasis-override: color-mix(
     in srgb,
     var(--code-background) 80%,
-    var(--success)
+    var(--diff-addition)
   );
 
   --diffs-bg-deletion-override: light-dark(
-    color-mix(in srgb, var(--code-background) 50%, var(--destructive)),
-    color-mix(in srgb, var(--code-background) 70%, var(--destructive))
+    color-mix(in srgb, var(--code-background) 50%, var(--diff-deletion)),
+    color-mix(in srgb, var(--code-background) 70%, var(--diff-deletion))
   );
   --diffs-bg-deletion-number-override: light-dark(
-    color-mix(in srgb, var(--code-background) 35%, var(--destructive)),
-    color-mix(in srgb, var(--code-background) 60%, var(--destructive))
+    color-mix(in srgb, var(--code-background) 35%, var(--diff-deletion)),
+    color-mix(in srgb, var(--code-background) 60%, var(--diff-deletion))
   );
   --diffs-bg-deletion-hover-override: color-mix(
     in srgb,
     var(--code-background) 85%,
-    var(--destructive)
+    var(--diff-deletion)
   );
   --diffs-bg-deletion-emphasis-override: color-mix(
     in srgb,
     var(--code-background) 80%,
-    var(--destructive)
+    var(--diff-deletion)
   );
 
   background-color: var(--diffs-bg) !important;
diff --git a/apps/web/src/routes/__root.tsx b/apps/web/src/routes/__root.tsx
index 23b1e4c582651578f9de04b88d02704e07c960ec..4c30320a311afd27c57d0c768f037f809ad433b3 100644
--- a/apps/web/src/routes/__root.tsx
+++ b/apps/web/src/routes/__root.tsx
@@ -226,6 +226,11 @@ function EnvironmentThemeSync() {
 
 function ContrastAppearanceSync() {
   const appearanceContrast = useClientSettings((settings) => settings.appearanceContrast);
+  const diffColorScheme = useClientSettings((settings) => settings.diffColorScheme);
+
+  useEffect(() => {
+    document.documentElement.dataset.diffColorScheme = diffColorScheme;
+  }, [diffColorScheme]);
 
   useEffect(() => {
     applyAppearanceContrast(document.documentElement, appearanceContrast);
diff --git a/packages/contracts/src/settings.test.ts b/packages/contracts/src/settings.test.ts
index 7d3cd2ceafe7fd18b66354bd3465d486f90ac180..8cbf0e55b9df1c396a2fcf373d06712ea5fd6622 100644
--- a/packages/contracts/src/settings.test.ts
+++ b/packages/contracts/src/settings.test.ts
@@ -135,6 +135,23 @@ describe("ClaudeSettings auto-compaction", () => {
   });
 });
 
+describe("ClientSettings diff colors", () => {
+  it("keeps red and green for existing settings without a saved palette", () => {
+    expect(decodeClientSettings({}).diffColorScheme).toBe("red-green");
+  });
+
+  it.each(["red-green", "blue-orange"])("round-trips the %s palette", (diffColorScheme) => {
+    const settings = decodeClientSettings({ diffColorScheme });
+    expect(encodeClientSettings(settings).diffColorScheme).toBe(diffColorScheme);
+    expect(decodeClientSettingsPatch({ diffColorScheme }).diffColorScheme).toBe(diffColorScheme);
+  });
+
+  it("rejects unsupported palettes", () => {
+    expect(() => decodeClientSettings({ diffColorScheme: "purple-yellow" })).toThrow();
+    expect(() => decodeClientSettingsPatch({ diffColorScheme: "purple-yellow" })).toThrow();
+  });
+});
+
 describe("ClientSettings load balancing", () => {
   it("requires opt-in when settings are new or omit load balancing", () => {
     expect(decodeClientSettings({}).loadBalancingEnabled).toBe(false);
diff --git a/packages/contracts/src/settings.ts b/packages/contracts/src/settings.ts
index 3491103da94fe1c6617d8ccf330e7b6d76edd055..9fd445d0899e9d3341c8eab48d58248b3685ba79 100644
--- a/packages/contracts/src/settings.ts
+++ b/packages/contracts/src/settings.ts
@@ -271,7 +271,12 @@ export const LoadBalancingWeights = Schema.Record(
   Schema.Int.check(Schema.isBetween({ minimum: 0, maximum: 100 })),
 );
 
+export const DiffColorScheme = Schema.Literals(["red-green", "blue-orange"]);
+
 export const ClientSettingsSchema = Schema.Struct({
+  diffColorScheme: DiffColorScheme.pipe(
+    Schema.withDecodingDefault(Effect.succeed("red-green" as const)),
+  ),
   loadBalancingEnabled: Schema.Boolean.pipe(Schema.withDecodingDefault(Effect.succeed(false))),
   loadBalancingWeights: LoadBalancingWeights.pipe(Schema.withDecodingDefault(Effect.succeed({}))),
   appearanceContrast: AppearanceContrast.pipe(
@@ -1295,6 +1300,7 @@ export const ServerSettingsPatch = Schema.Struct({
 export type ServerSettingsPatch = typeof ServerSettingsPatch.Type;
 
 export const ClientSettingsPatch = Schema.Struct({
+  diffColorScheme: Schema.optionalKey(DiffColorScheme),
   loadBalancingEnabled: Schema.optionalKey(Schema.Boolean),
   loadBalancingWeights: Schema.optionalKey(LoadBalancingWeights),
   appearanceContrast: Schema.optionalKey(AppearanceContrast),