diff --git a/desktop/src/shared/styles/globals/markdown.css b/desktop/src/shared/styles/globals/markdown.css
index 135c036e74c..251fdb525c2 100644
--- a/desktop/src/shared/styles/globals/markdown.css
+++ b/desktop/src/shared/styles/globals/markdown.css
@@ -303,21 +303,6 @@
   color: hsl(var(--primary) / 0.9);
 }
 
-/* @mentions use an opaque highlighter-yellow treatment so they scan
-   differently from channel links while retaining AA contrast on every theme.
-   Shared by human and agent chips in both timeline and composer. */
-.message-markdown .mention-chip.inline-chip-icon-human,
-.message-markdown .mention-chip.inline-chip-icon-agent {
-  background: hsl(var(--mention-highlight));
-  color: hsl(var(--buzz-content-dark));
-}
-
-.message-markdown .mention-chip-hover.inline-chip-icon-human:hover,
-.message-markdown .mention-chip-hover.inline-chip-icon-agent:hover {
-  background: hsl(var(--mention-highlight-hover));
-  color: hsl(var(--buzz-content-dark));
-}
-
 .message-markdown .mention-prefix-hidden {
   display: inline-block;
   width: 0;
diff --git a/desktop/src/shared/styles/globals/theme.css b/desktop/src/shared/styles/globals/theme.css
index 875a17aedfc..9b55da2703f 100644
--- a/desktop/src/shared/styles/globals/theme.css
+++ b/desktop/src/shared/styles/globals/theme.css
@@ -32,10 +32,6 @@
        destructive, these must stay recognizably red with AA label contrast. */
     --notification: 348 65% 48%;
     --notification-foreground: 350 100% 98%;
-    /* Opaque highlighter colors keep near-black mention text readable on every
-       message surface instead of depending on the active theme underneath. */
-    --mention-highlight: 48 96% 70%;
-    --mention-highlight-hover: 48 96% 62%;
     --border: 225 13.56% 76.86%;
     --input: 225 13.56% 76.86%;
     --ring: 234 16.02% 35.49%;
diff --git a/desktop/tests/e2e/mentions.spec.ts b/desktop/tests/e2e/mentions.spec.ts
index e90281a52fa..6726a224024 100644
--- a/desktop/tests/e2e/mentions.spec.ts
+++ b/desktop/tests/e2e/mentions.spec.ts
@@ -39,37 +39,6 @@ const DM_THREAD_AGENT_MENTION_ERROR_TEXT =
 const DM_THREAD_MEMBERS_LOADING_ERROR_TEXT =
   "Checking conversation members. Try again in a moment.";
 
-async function expectTextContrast(
-  locator: import("@playwright/test").Locator,
-  minimum = 4.5,
-) {
-  const contrastRatio = await locator.evaluate((element) => {
-    const parseRgb = (value: string) =>
-      (value.match(/[\d.]+/g) ?? []).slice(0, 3).map(Number);
-    const luminance = (color: number[]) =>
-      color
-        .map((channel) => {
-          const value = channel / 255;
-          return value <= 0.04045
-            ? value / 12.92
-            : ((value + 0.055) / 1.055) ** 2.4;
-        })
-        .reduce(
-          (sum, channel, index) =>
-            sum + channel * [0.2126, 0.7152, 0.0722][index],
-          0,
-        );
-    const style = getComputedStyle(element);
-    const foreground = luminance(parseRgb(style.color));
-    const background = luminance(parseRgb(style.backgroundColor));
-    return (
-      (Math.max(foreground, background) + 0.05) /
-      (Math.min(foreground, background) + 0.05)
-    );
-  });
-  expect(contrastRatio).toBeGreaterThanOrEqual(minimum);
-}
-
 /** Locator scoped to the mention autocomplete dropdown inside the composer. */
 function autocomplete(page: import("@playwright/test").Page) {
   return page
@@ -2749,9 +2718,6 @@ test("sent non-member person mention uses the normal mention style", async ({
 test("sent managed non-member agent mention uses the agent mention style", async ({
   page,
 }) => {
-  await page.addInitScript(() => {
-    window.localStorage.setItem("buzz-theme", "buzz-dark");
-  });
   await installMockBridge(page, {
     managedAgents: [
       {
@@ -2781,13 +2747,6 @@ test("sent managed non-member agent mention uses the agent mention style", async
   await expect(mentionChip).toBeVisible();
   await expect(mentionChip).toHaveText("charlie");
   await expect(mentionChip).toHaveClass(/agent-mention-highlight/);
-  await expect(mentionChip).toHaveCSS("background-color", "rgb(252, 223, 105)");
-  await expect(mentionChip).toHaveCSS("color", "rgb(26, 26, 26)");
-  await expectTextContrast(mentionChip);
-  await mentionChip.hover();
-  await expect(mentionChip).toHaveCSS("background-color", "rgb(251, 214, 65)");
-  await expect(mentionChip).toHaveCSS("color", "rgb(26, 26, 26)");
-  await expectTextContrast(mentionChip);
 });
 
 test("mention button opens autocomplete and inserts a selected member", async ({
@@ -2893,13 +2852,6 @@ test("mention text is highlighted in sent messages", async ({ page }) => {
   await expect(mentionChip).toBeVisible();
   await expect(mentionChip).toHaveText("bob");
   await expect(mentionChip).toHaveClass(/inline-chip-icon-human/);
-  await expect(mentionChip).toHaveCSS("background-color", "rgb(252, 223, 105)");
-  await expect(mentionChip).toHaveCSS("color", "rgb(26, 26, 26)");
-  await expectTextContrast(mentionChip);
-  await mentionChip.hover();
-  await expect(mentionChip).toHaveCSS("background-color", "rgb(251, 214, 65)");
-  await expect(mentionChip).toHaveCSS("color", "rgb(26, 26, 26)");
-  await expectTextContrast(mentionChip);
 });
 
 test("clicking author name opens user profile panel", async ({ page }) => {