From 22ad26f24c79604242087bf171ba434d62eed50d Mon Sep 17 00:00:00 2001
From: usrnk1 <7547651+usrnk1@users.noreply.github.com>
Date: Mon, 19 Oct 2026 16:40:55 +0200
Subject: [PATCH] feat(app): add reduce motion appearance setting (#57103)

---
 packages/app/src/index.css                    |  4 +--
 packages/app/src/new-session/pin-board.tsx    |  3 ++-
 packages/app/src/runtime/i18n/en.ts           |  5 ++++
 .../src/session/composer/activity-chips.css   |  2 +-
 .../app/src/session/timeline/virtualizer.tsx  |  3 ++-
 .../src/settings/about/animated-wordmark.tsx  |  3 ++-
 .../src/settings/appearance/appearance.tsx    | 22 ++++++++++++++++
 .../app/src/settings/general/controllers.ts   |  5 ++++
 packages/app/src/settings/model.test.ts       |  2 ++
 packages/app/src/settings/model.tsx           | 20 +++++++++++++-
 packages/app/src/settings/search-catalog.ts   |  6 +++++
 packages/app/src/settings/search.css          |  2 +-
 packages/app/src/settings/settings.css        |  6 ++---
 .../app/src/settings/workspaces/project.css   |  2 +-
 packages/app/src/shell/mobile-drawer.css      |  2 +-
 packages/app/src/shell/titlebar/tab-nav.css   |  2 +-
 .../app/src/shell/titlebar/tab-popover.css    |  2 +-
 .../gui-extensions/src/browser/comment.css    |  2 +-
 .../gui-extensions/src/details/details.css    |  2 +-
 .../session-ui/src/components/basic-tool.css  |  2 +-
 .../session-ui/src/components/markdown.css    |  2 +-
 .../src/components/message-part.css           |  4 +--
 .../src/components/question-prompt.css        |  2 +-
 .../src/components/tool-count-label.css       |  2 +-
 .../src/components/tool-count-summary.css     |  2 +-
 .../src/components/tool-status-title.css      |  2 +-
 .../session-progress-indicator-v2.css         |  2 +-
 packages/storybook/.storybook/preview.tsx     | 15 +++++++++++
 .../ui/src/components/animated-number.css     |  2 +-
 packages/ui/src/components/text-reveal.css    |  2 +-
 .../ui/src/components/text-strikethrough.css  |  2 +-
 packages/ui/src/feedback/loader/loader.css    |  2 +-
 packages/ui/src/feedback/toast/toast.css      |  2 +-
 packages/ui/src/feedback/toast/toast.tsx      |  3 ++-
 packages/ui/src/motion/README.md              |  2 +-
 packages/ui/src/motion/reduced.ts             | 26 +++++++++++++++++--
 .../segmented-control/segmented-control.tsx   |  5 ++--
 packages/ui/src/overlays/tooltip/tooltip.css  |  2 +-
 packages/ui/src/styles/tailwind/index.css     |  4 +++
 .../typography/text-shimmer/text-shimmer.css  |  2 +-
 40 files changed, 142 insertions(+), 40 deletions(-)

diff --git a/packages/app/src/index.css b/packages/app/src/index.css
index db868801aa9..d1eb442a50b 100644
--- a/packages/app/src/index.css
+++ b/packages/app/src/index.css
@@ -178,7 +178,7 @@
     transform-origin: 50% 50%;
   }
 
-  @media (prefers-reduced-motion: reduce) {
+  :root[data-motion="reduce"] {
     [data-slot="titlebar-update-loader"] {
       animation: none;
     }
@@ -262,7 +262,7 @@
     --session-dropzone-card: var(--v2-background-bg-layer-01);
   }
 
-  @media (prefers-reduced-motion: reduce) {
+  :root[data-motion="reduce"] {
     [data-component="session-dropzone"][data-visible="true"],
     [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-content"],
     [data-component="session-dropzone"][data-visible="true"] [data-slot="session-dropzone-upload"],
diff --git a/packages/app/src/new-session/pin-board.tsx b/packages/app/src/new-session/pin-board.tsx
index f8760e2a382..e79a6ec3054 100644
--- a/packages/app/src/new-session/pin-board.tsx
+++ b/packages/app/src/new-session/pin-board.tsx
@@ -1,6 +1,7 @@
 import { onCleanup, onMount } from "solid-js"
 import { createQuads, type Quads, type Rgba } from "./pin-quads"
 import { PinSound } from "./pin-sound"
+import { prefersReducedMotion } from "@opencode/ui/motion"
 
 // The wordmark as a 78×14 pin grid: 1 = counter shadow, 2 = "open", 3 = "code".
 const GRID = [
@@ -98,7 +99,7 @@ function mountPinBoard(back: HTMLCanvasElement, front: HTMLCanvasElement, logo:
   const stage = back.parentElement!
   // The pins behind the composer and the ones popped in front of it are each one layer of quads.
   const layers = { back: createQuads(back, () => wake()), front: createQuads(front, () => wake()) }
-  const still = matchMedia("(prefers-reduced-motion: reduce)").matches
+  const still = prefersReducedMotion()
   const pins: Pin[] = GRID.flatMap((row, r) =>
     [...row].flatMap((ch, c) => (ch === "." ? [] : [createPin(c, r, Number(ch))])),
   )
diff --git a/packages/app/src/runtime/i18n/en.ts b/packages/app/src/runtime/i18n/en.ts
index fd7030312a0..df60d4ce141 100644
--- a/packages/app/src/runtime/i18n/en.ts
+++ b/packages/app/src/runtime/i18n/en.ts
@@ -753,6 +753,11 @@ export const dict = {
   "settings.general.row.interfaceMode.inbox.description":
     "Every session across your servers, sorted by what needs you next.",
   "settings.general.row.interfaceMode.experimental": "Experimental",
+  "settings.appearance.row.reduceMotion.title": "Reduce motion",
+  "settings.appearance.row.reduceMotion.description": "Reduce animations or match your system",
+  "settings.appearance.row.reduceMotion.system": "System",
+  "settings.appearance.row.reduceMotion.on": "On",
+  "settings.appearance.row.reduceMotion.off": "Off",
   "settings.notifications.description": "Choose when to receive notifications and hear sounds",
   "settings.shortcuts.description": "Customize shortcuts for common actions",
   "settings.servers.description": "Manage server connections",
diff --git a/packages/app/src/session/composer/activity-chips.css b/packages/app/src/session/composer/activity-chips.css
index 205209ffd35..646f1382658 100644
--- a/packages/app/src/session/composer/activity-chips.css
+++ b/packages/app/src/session/composer/activity-chips.css
@@ -56,7 +56,7 @@
     margin: 4px -4px;
   }
 
-  @media (prefers-reduced-motion: reduce) {
+  :root[data-motion="reduce"] & {
     animation: none;
   }
 }
diff --git a/packages/app/src/session/timeline/virtualizer.tsx b/packages/app/src/session/timeline/virtualizer.tsx
index a78d1e92ce3..8f0e1042a3e 100644
--- a/packages/app/src/session/timeline/virtualizer.tsx
+++ b/packages/app/src/session/timeline/virtualizer.tsx
@@ -28,6 +28,7 @@ import { createMediaQuery } from "@solid-primitives/media"
 import type { createTimelineProjection } from "./projection"
 import { observeElementOffsetReconnectAware } from "./observe-element-offset"
 import { filterVirtualIndexes } from "./virtual-items"
+import { prefersReducedMotion } from "@opencode/ui/motion"
 
 const fallbackItemSize = 60
 
@@ -869,7 +870,7 @@ export function createTimelineVirtualizer(input: Input) {
               "box-shadow": "var(--v2-elevation-raised), 0px 2px 8px var(--v2-background-bg-base)",
             }}
             onClick={() =>
-              input.onResumeScroll(matchMedia("(prefers-reduced-motion: reduce)").matches ? "auto" : "smooth")
+              input.onResumeScroll(prefersReducedMotion() ? "auto" : "smooth")
             }
           >
             <svg width="16" height="16" viewBox="0 0 16 16" fill="none" aria-hidden="true">
diff --git a/packages/app/src/settings/about/animated-wordmark.tsx b/packages/app/src/settings/about/animated-wordmark.tsx
index c7396043712..117e2f2534b 100644
--- a/packages/app/src/settings/about/animated-wordmark.tsx
+++ b/packages/app/src/settings/about/animated-wordmark.tsx
@@ -1,5 +1,6 @@
 import { createEffect, For, on, onCleanup } from "solid-js"
 import { createStore } from "solid-js/store"
+import { prefersReducedMotion } from "@opencode/ui/motion"
 
 const target = ["o", "p", "e", "n", "c", "o", "d", "e"] as const
 
@@ -16,7 +17,7 @@ export function AnimatedWordmark(props: { active: boolean }) {
         timers.forEach(clearTimeout)
         timers.clear()
 
-        if (!active || matchMedia("(prefers-reduced-motion: reduce)").matches) {
+        if (!active || prefersReducedMotion()) {
           setState("letters", [...target])
 
           return
diff --git a/packages/app/src/settings/appearance/appearance.tsx b/packages/app/src/settings/appearance/appearance.tsx
index 6f0a2e92634..4dd7be3bf95 100644
--- a/packages/app/src/settings/appearance/appearance.tsx
+++ b/packages/app/src/settings/appearance/appearance.tsx
@@ -10,6 +10,12 @@ import "@/settings/settings.css"
 
 const schemeOptions: ("system" | "light" | "dark")[] = ["system", "light", "dark"]
 
+const reduceMotionOptions = [
+  { value: "system" as const, label: "settings.appearance.row.reduceMotion.system" as const },
+  { value: "on" as const, label: "settings.appearance.row.reduceMotion.on" as const },
+  { value: "off" as const, label: "settings.appearance.row.reduceMotion.off" as const },
+]
+
 const fontSettings = {
   ui: {
     action: "settings-ui-font",
@@ -128,6 +134,22 @@ export const SettingsAppearance: Component = () => {
             <FontSetting kind="ui" fonts={appearance.fonts} />
             <FontSetting kind="code" fonts={appearance.fonts} />
             <FontSetting kind="terminal" fonts={appearance.fonts} />
+
+            <SettingsRow
+              title={language.t("settings.appearance.row.reduceMotion.title")}
+              description={language.t("settings.appearance.row.reduceMotion.description")}
+            >
+              <Select
+                data-action="settings-reduce-motion"
+                options={reduceMotionOptions}
+                current={reduceMotionOptions.find((option) => option.value === appearance.reduceMotion.current())}
+                placement="bottom-end"
+                gutter={6}
+                value={(option) => option.value}
+                label={(option) => language.t(option.label)}
+                onSelect={(option) => option && appearance.reduceMotion.select(option.value)}
+              />
+            </SettingsRow>
           </SettingsList>
         </div>
       </div>
diff --git a/packages/app/src/settings/general/controllers.ts b/packages/app/src/settings/general/controllers.ts
index e6e7c3df0ce..5002f36f519 100644
--- a/packages/app/src/settings/general/controllers.ts
+++ b/packages/app/src/settings/general/controllers.ts
@@ -8,6 +8,7 @@ import {
   sansDefault,
   sansFontFamily,
   sansInput,
+  type ReduceMotion,
   terminalDefault,
   terminalFontFamily,
   terminalInput,
@@ -90,6 +91,10 @@ export function createAppearanceSettingsController() {
       current: createMemo(() => themes().find((option) => option.id === theme.themeId())),
       select: (option: { id: string } | null) => option && theme.setTheme(option.id),
     },
+    reduceMotion: {
+      current: settings.appearance.reduceMotion,
+      select: (value: ReduceMotion) => settings.appearance.setReduceMotion(value),
+    },
     fonts: {
       ui: createMemo(() => ({
         value: sansInput(settings.appearance.uiFont()),
diff --git a/packages/app/src/settings/model.test.ts b/packages/app/src/settings/model.test.ts
index 60c937e06d6..0f0b695c138 100644
--- a/packages/app/src/settings/model.test.ts
+++ b/packages/app/src/settings/model.test.ts
@@ -104,6 +104,7 @@ describe("settings schema", () => {
         sans: "",
         terminal: "",
         tabLayout: "horizontal",
+        reduceMotion: "system",
       },
       keybinds: {},
       permissions: { autoApprove: false, autoApproveProjects: {} },
@@ -150,6 +151,7 @@ describe("settings schema", () => {
       sans: "",
       terminal: "",
       tabLayout: "vertical",
+      reduceMotion: "system",
     })
     expect(settings.permissions).toEqual({ autoApprove: true, autoApproveProjects: { on: true, off: false } })
     expect(settings.workspaces).toEqual({ defaultDestination: "new", lastUsed: { good: "workspace" } })
diff --git a/packages/app/src/settings/model.tsx b/packages/app/src/settings/model.tsx
index 052bd9b49c3..0a7888ce553 100644
--- a/packages/app/src/settings/model.tsx
+++ b/packages/app/src/settings/model.tsx
@@ -1,5 +1,6 @@
 import { produce, reconcile, unwrap } from "solid-js/store"
 import { createEffect, createMemo } from "solid-js"
+import { createMediaQuery } from "@solid-primitives/media"
 import { Effect, Option, Predicate, Schema, SchemaGetter } from "effect"
 import { createSimpleContext } from "@opencode/ui/context"
 import { timelinePresets, type TimelineCategory, type TimelineDetail } from "@opencode/session-ui/timeline/detail"
@@ -17,6 +18,8 @@ export type FollowUpBehavior = Settings["general"]["followUpBehavior"]
 
 export type TabLayout = Settings["appearance"]["tabLayout"]
 
+export type ReduceMotion = Settings["appearance"]["reduceMotion"]
+
 export type NotificationSettings = Settings["notifications"]
 
 export type SoundSettings = Settings["sounds"]
@@ -132,6 +135,7 @@ const appearanceSchema = Persistence.struct({
   // "inbox" is experimental: the vertical layout with a server-wide session inbox in place of tabs.
   tabLayout: Schema.Literals(["horizontal", "vertical", "inbox"]),
   sidebarOpen: Persistence.optional(Schema.Boolean),
+  reduceMotion: Schema.Literals(["system", "on", "off"]),
 })
 
 const permissionsSchema = Persistence.struct({
@@ -287,7 +291,7 @@ export const defaultSettings: Settings = {
     mobileTitlebarPosition: "top",
     followUpBehavior: "steer",
   },
-  appearance: { fontSize: 14, mono: "", sans: "", terminal: "", tabLayout: "horizontal" },
+  appearance: { fontSize: 14, mono: "", sans: "", terminal: "", tabLayout: "horizontal", reduceMotion: "system" },
   keybinds: {},
   permissions: { autoApprove: false, autoApproveProjects: {} },
   workspaces: { defaultDestination: "last-used", lastUsed: {} },
@@ -330,6 +334,16 @@ export const { use: useSettings, provider: SettingsProvider } = createSimpleCont
       void document.fonts?.load(`440 13px ${mono}`).catch(() => undefined)
     })
 
+    const reduceMotion = withFallback(() => store.appearance?.reduceMotion, defaultSettings.appearance.reduceMotion)
+    const systemReducedMotion = createMediaQuery("(prefers-reduced-motion: reduce)")
+
+    // Motion styles key off this attribute instead of the media query so the setting can override the system.
+    createEffect(() => {
+      if (typeof document === "undefined") return
+      const reduce = reduceMotion() === "system" ? systemReducedMotion() : reduceMotion() === "on"
+      document.documentElement.dataset.motion = reduce ? "reduce" : "full"
+    })
+
     const autoApproveDefault = withFallback(
       () => store.permissions?.autoApprove,
       defaultSettings.permissions.autoApprove,
@@ -406,6 +420,10 @@ export const { use: useSettings, provider: SettingsProvider } = createSimpleCont
         setSidebarOpen(value: boolean) {
           setStore("appearance", "sidebarOpen", value)
         },
+        reduceMotion,
+        setReduceMotion(value: ReduceMotion) {
+          setStore("appearance", "reduceMotion", value)
+        },
       },
       keybinds: {
         get: (action: string) => store.keybinds?.[action],
diff --git a/packages/app/src/settings/search-catalog.ts b/packages/app/src/settings/search-catalog.ts
index 8eaff2421e6..7aff189906c 100644
--- a/packages/app/src/settings/search-catalog.ts
+++ b/packages/app/src/settings/search-catalog.ts
@@ -106,6 +106,12 @@ export const clientSettings: Entry<SettingsRootTab>[] = [
     target: "settings-terminal-font",
     keywords: "terminal typeface",
   },
+  {
+    tab: "appearance",
+    label: "settings.appearance.row.reduceMotion.title",
+    target: "settings-reduce-motion",
+    keywords: "animation accessibility",
+  },
   {
     tab: "notifications",
     label: "settings.general.notifications.agent.title",
diff --git a/packages/app/src/settings/search.css b/packages/app/src/settings/search.css
index 29e160ab0cd..df2e620016f 100644
--- a/packages/app/src/settings/search.css
+++ b/packages/app/src/settings/search.css
@@ -295,7 +295,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-search-target]::before {
     animation-timing-function: steps(1, end);
   }
diff --git a/packages/app/src/settings/settings.css b/packages/app/src/settings/settings.css
index 682081af199..7292a8b84da 100644
--- a/packages/app/src/settings/settings.css
+++ b/packages/app/src/settings/settings.css
@@ -943,7 +943,7 @@
   opacity: 1;
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   .settings-provider-console-chevron {
     transition: none;
   }
@@ -1459,7 +1459,7 @@
   padding-block: 2px;
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   .settings-models-group-chevron svg,
   .provider-model-group-chevron {
     transition: none;
@@ -1709,7 +1709,7 @@
   overflow: hidden;
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   .settings-workspaces-row-motion {
     transition: none;
   }
diff --git a/packages/app/src/settings/workspaces/project.css b/packages/app/src/settings/workspaces/project.css
index 802f8e4d351..50cecdef44d 100644
--- a/packages/app/src/settings/workspaces/project.css
+++ b/packages/app/src/settings/workspaces/project.css
@@ -327,7 +327,7 @@
   unicode-bidi: isolate;
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   .project-settings-icon-overlay,
   .project-settings-color,
   .project-settings-shared-chevron {
diff --git a/packages/app/src/shell/mobile-drawer.css b/packages/app/src/shell/mobile-drawer.css
index 255e3e087c8..2ba731a3d4a 100644
--- a/packages/app/src/shell/mobile-drawer.css
+++ b/packages/app/src/shell/mobile-drawer.css
@@ -77,7 +77,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-slot="mobile-drawer-content"][data-transitioning],
   [data-slot="mobile-drawer-content"][data-closing] {
     transition: none;
diff --git a/packages/app/src/shell/titlebar/tab-nav.css b/packages/app/src/shell/titlebar/tab-nav.css
index bfd734ca580..448b53e15c2 100644
--- a/packages/app/src/shell/titlebar/tab-nav.css
+++ b/packages/app/src/shell/titlebar/tab-nav.css
@@ -403,7 +403,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-titlebar-tab] [data-slot="tab-prompt-pulse"] {
     animation: none;
   }
diff --git a/packages/app/src/shell/titlebar/tab-popover.css b/packages/app/src/shell/titlebar/tab-popover.css
index e65a3fe8dac..212b3131e06 100644
--- a/packages/app/src/shell/titlebar/tab-popover.css
+++ b/packages/app/src/shell/titlebar/tab-popover.css
@@ -121,7 +121,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="session-tab-popover"],
   [data-component="session-tab-popover"][data-closed] {
     animation: none;
diff --git a/packages/gui-extensions/src/browser/comment.css b/packages/gui-extensions/src/browser/comment.css
index 803eeeb0860..a0ac333aacc 100644
--- a/packages/gui-extensions/src/browser/comment.css
+++ b/packages/gui-extensions/src/browser/comment.css
@@ -28,7 +28,7 @@
   transform-origin: top left;
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="browser-comment"],
   [data-component="browser-comment"] [data-slot="browser-comment-editor"] {
     animation: none;
diff --git a/packages/gui-extensions/src/details/details.css b/packages/gui-extensions/src/details/details.css
index 57163e936da..6ed5132115b 100644
--- a/packages/gui-extensions/src/details/details.css
+++ b/packages/gui-extensions/src/details/details.css
@@ -314,7 +314,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   .session-summary-popover,
   .session-service-menu {
     animation: none;
diff --git a/packages/session-ui/src/components/basic-tool.css b/packages/session-ui/src/components/basic-tool.css
index bd409fe2137..0c5a98afd26 100644
--- a/packages/session-ui/src/components/basic-tool.css
+++ b/packages/session-ui/src/components/basic-tool.css
@@ -312,7 +312,7 @@
       transform: none;
     }
 
-    @media (prefers-reduced-motion: reduce) {
+    :root[data-motion="reduce"] & {
       transition: none;
     }
   }
diff --git a/packages/session-ui/src/components/markdown.css b/packages/session-ui/src/components/markdown.css
index 1135bbe62e8..dac523e1ce8 100644
--- a/packages/session-ui/src/components/markdown.css
+++ b/packages/session-ui/src/components/markdown.css
@@ -441,7 +441,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="markdown"] :is([data-markdown-word], code)[data-markdown-enter] {
     animation: none;
   }
diff --git a/packages/session-ui/src/components/message-part.css b/packages/session-ui/src/components/message-part.css
index f30c1d85ee5..bc25361b052 100644
--- a/packages/session-ui/src/components/message-part.css
+++ b/packages/session-ui/src/components/message-part.css
@@ -179,7 +179,7 @@
       background-color 150ms ease-out,
       color 150ms ease-out;
 
-    @media (prefers-reduced-motion: reduce) {
+    :root[data-motion="reduce"] & {
       transition: none;
     }
 
@@ -1411,7 +1411,7 @@
       opacity: 1;
     }
 
-    @media (prefers-reduced-motion: reduce) {
+    :root[data-motion="reduce"] & {
       transition: none;
     }
   }
diff --git a/packages/session-ui/src/components/question-prompt.css b/packages/session-ui/src/components/question-prompt.css
index 6c55370b86d..537cb16340b 100644
--- a/packages/session-ui/src/components/question-prompt.css
+++ b/packages/session-ui/src/components/question-prompt.css
@@ -430,7 +430,7 @@
     }
   }
 
-  @media (prefers-reduced-motion: reduce) {
+  :root[data-motion="reduce"] & {
     [data-slot="question-option"],
     .question-custom-field[data-component="text-input-v2"] {
       transition: none;
diff --git a/packages/session-ui/src/components/tool-count-label.css b/packages/session-ui/src/components/tool-count-label.css
index 11a33ff5d14..8a7013b10ce 100644
--- a/packages/session-ui/src/components/tool-count-label.css
+++ b/packages/session-ui/src/components/tool-count-label.css
@@ -50,7 +50,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="tool-count-label"] [data-slot="tool-count-label-suffix"] {
     transition-duration: 0ms;
   }
diff --git a/packages/session-ui/src/components/tool-count-summary.css b/packages/session-ui/src/components/tool-count-summary.css
index da8455267cc..f6a4a027587 100644
--- a/packages/session-ui/src/components/tool-count-summary.css
+++ b/packages/session-ui/src/components/tool-count-summary.css
@@ -93,7 +93,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="tool-count-summary"] [data-slot="tool-count-summary-empty"],
   [data-component="tool-count-summary"] [data-slot="tool-count-summary-item"],
   [data-component="tool-count-summary"] [data-slot="tool-count-summary-prefix"] {
diff --git a/packages/session-ui/src/components/tool-status-title.css b/packages/session-ui/src/components/tool-status-title.css
index d4415bd2daf..6e6daa484d9 100644
--- a/packages/session-ui/src/components/tool-status-title.css
+++ b/packages/session-ui/src/components/tool-status-title.css
@@ -76,7 +76,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="tool-status-title"] [data-slot="tool-status-swap"],
   [data-component="tool-status-title"] [data-slot="tool-status-tail"] {
     transition-duration: 0ms;
diff --git a/packages/session-ui/src/v2/components/session-progress-indicator-v2.css b/packages/session-ui/src/v2/components/session-progress-indicator-v2.css
index 1f705e088bd..d320eb01de6 100644
--- a/packages/session-ui/src/v2/components/session-progress-indicator-v2.css
+++ b/packages/session-ui/src/v2/components/session-progress-indicator-v2.css
@@ -14,7 +14,7 @@
   fill: currentColor;
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="session-progress-indicator-v2"] [data-frame-content] {
     display: none;
   }
diff --git a/packages/storybook/.storybook/preview.tsx b/packages/storybook/.storybook/preview.tsx
index a27fce926dc..3fa6b47b0eb 100644
--- a/packages/storybook/.storybook/preview.tsx
+++ b/packages/storybook/.storybook/preview.tsx
@@ -52,6 +52,20 @@ const Direction = (props: { value?: unknown }) => {
   return null
 }
 
+// The app derives this attribute from its reduce motion setting; stories follow the system preference.
+const Motion = () => {
+  onMount(() => {
+    const query = matchMedia("(prefers-reduced-motion: reduce)")
+    const apply = () => {
+      document.documentElement.dataset.motion = query.matches ? "reduce" : "full"
+    }
+    apply()
+    query.addEventListener("change", apply)
+    onCleanup(() => query.removeEventListener("change", apply))
+  })
+  return null
+}
+
 const BodyTypography = () => {
   onMount(() => {
     document.body.classList.add("font-(family-name:--font-family-text)", "text-[13px]", "font-[440]")
@@ -74,6 +88,7 @@ const frame = createJSXDecorator((Story, context) => {
           <UiI18nBridge>
             <Scheme value={scheme} />
             <Direction value={context.globals?.direction} />
+            <Motion />
             <BodyTypography />
             <DialogProvider>
               <MarkedProvider>
diff --git a/packages/ui/src/components/animated-number.css b/packages/ui/src/components/animated-number.css
index 60fa626ed72..e10c64750ef 100644
--- a/packages/ui/src/components/animated-number.css
+++ b/packages/ui/src/components/animated-number.css
@@ -88,7 +88,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="animated-number"] [data-slot="animated-number-value"][data-resizing] {
     transition-duration: 0ms;
   }
diff --git a/packages/ui/src/components/text-reveal.css b/packages/ui/src/components/text-reveal.css
index f799962f094..20cbc19fe9c 100644
--- a/packages/ui/src/components/text-reveal.css
+++ b/packages/ui/src/components/text-reveal.css
@@ -138,7 +138,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="text-reveal"] [data-slot="text-reveal-track"] {
     transition-duration: 0ms !important;
   }
diff --git a/packages/ui/src/components/text-strikethrough.css b/packages/ui/src/components/text-strikethrough.css
index 1be80546838..3c8d7b3a069 100644
--- a/packages/ui/src/components/text-strikethrough.css
+++ b/packages/ui/src/components/text-strikethrough.css
@@ -20,7 +20,7 @@
   pointer-events: none;
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-slot="text-strikethrough-line"] {
     clip-path: none !important;
   }
diff --git a/packages/ui/src/feedback/loader/loader.css b/packages/ui/src/feedback/loader/loader.css
index 5d7e10bb97e..2268ff5700d 100644
--- a/packages/ui/src/feedback/loader/loader.css
+++ b/packages/ui/src/feedback/loader/loader.css
@@ -25,7 +25,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="loader-v2"] {
     animation: none;
   }
diff --git a/packages/ui/src/feedback/toast/toast.css b/packages/ui/src/feedback/toast/toast.css
index 24fa71de120..a6525756f8a 100644
--- a/packages/ui/src/feedback/toast/toast.css
+++ b/packages/ui/src/feedback/toast/toast.css
@@ -215,7 +215,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   .toast-v2,
   .toast-v2 > * {
     animation: none !important;
diff --git a/packages/ui/src/feedback/toast/toast.tsx b/packages/ui/src/feedback/toast/toast.tsx
index d4347503741..e794b61a453 100644
--- a/packages/ui/src/feedback/toast/toast.tsx
+++ b/packages/ui/src/feedback/toast/toast.tsx
@@ -7,6 +7,7 @@ import { Portal } from "solid-js/web"
 import { useI18n } from "../../context/i18n"
 import "../../actions/button/button.css"
 import "./toast.css"
+import { prefersReducedMotion } from "../../motion"
 
 export interface ToastRegionProps extends ToasterProps {}
 
@@ -307,7 +308,7 @@ function pulseToast(toastId: number) {
   requestAnimationFrame(() => {
     const element = document.querySelector<HTMLElement>(`[data-testid="toast-v2-${toastId}"]`)
 
-    if (!element || window.matchMedia("(prefers-reduced-motion: reduce)").matches) return
+    if (!element || prefersReducedMotion()) return
     element.animate([{ scale: 1 }, { scale: 1.025 }, { scale: 1 }], { duration: 160, easing: "ease-out" })
   })
 }
diff --git a/packages/ui/src/motion/README.md b/packages/ui/src/motion/README.md
index 7eef4d92f39..f5cda9c86f9 100644
--- a/packages/ui/src/motion/README.md
+++ b/packages/ui/src/motion/README.md
@@ -34,7 +34,7 @@ const frameLoop: {
 }
 function createFrameLoop(scheduler?: { request(callback: (time: number) => void): number; cancel(id: number): void })
 
-const prefersReducedMotion: () => boolean // live matchMedia
+const prefersReducedMotion: () => boolean // root data-motion, else live matchMedia
 function observeReducedMotion(listener: () => void): () => void
 
 class VelocityTracker {
diff --git a/packages/ui/src/motion/reduced.ts b/packages/ui/src/motion/reduced.ts
index c6f5accfb77..a20b9e83e28 100644
--- a/packages/ui/src/motion/reduced.ts
+++ b/packages/ui/src/motion/reduced.ts
@@ -26,7 +26,20 @@ function media(): MediaQueryList | undefined {
   return result
 }
 
-export const prefersReducedMotion = (): boolean => media()?.matches ?? false
+// The app resolves its reduce motion setting into this attribute; without it the system preference applies.
+function override(): boolean | undefined {
+  const value = globalThis.document?.documentElement.getAttribute("data-motion")
+
+  if (value === "reduce") return true
+
+  if (value === "full") return false
+
+  return undefined
+}
+
+let attribute: MutationObserver | undefined
+
+export const prefersReducedMotion = (): boolean => override() ?? media()?.matches ?? false
 
 /** Also settle active WAAPI jobs when the preference changes mid-animation. SSR-safe. */
 export function observeReducedMotion(listener: () => void): () => void {
@@ -34,11 +47,20 @@ export function observeReducedMotion(listener: () => void): () => void {
 
   if (!preference) return () => {}
 
-  if (listeners.size === 0) preference.addEventListener("change", notify)
+  if (listeners.size === 0) {
+    preference.addEventListener("change", notify)
+
+    if (globalThis.document && globalThis.MutationObserver) {
+      attribute = new MutationObserver(notify)
+      attribute.observe(document.documentElement, { attributes: true, attributeFilter: ["data-motion"] })
+    }
+  }
   listeners.add(listener)
 
   return () => {
     if (!listeners.delete(listener) || listeners.size > 0) return
     result?.removeEventListener("change", notify)
+    attribute?.disconnect()
+    attribute = undefined
   }
 }
diff --git a/packages/ui/src/navigation/segmented-control/segmented-control.tsx b/packages/ui/src/navigation/segmented-control/segmented-control.tsx
index 381d6d960b5..0ef0be0f5a4 100644
--- a/packages/ui/src/navigation/segmented-control/segmented-control.tsx
+++ b/packages/ui/src/navigation/segmented-control/segmented-control.tsx
@@ -16,6 +16,7 @@ import {
   type ParentProps,
 } from "solid-js"
 import "./segmented-control.css"
+import { prefersReducedMotion } from "../../motion"
 
 type OnChange = (value: string | null) => void
 
@@ -108,8 +109,6 @@ export function SegmentedControl(props: SegmentedControlProps) {
 
   const selected = createMemo(() => (isControlled() ? (local.value ?? null) : internal()))
 
-  const reducedMotion = () => globalThis.matchMedia?.("(prefers-reduced-motion: reduce)")?.matches === true
-
   const x = useMotionValue(0)
   const width = useMotionValue(0)
 
@@ -135,7 +134,7 @@ export function SegmentedControl(props: SegmentedControlProps) {
 
     target = next
 
-    if (!ready() || !shouldAnimate || reducedMotion()) {
+    if (!ready() || !shouldAnimate || prefersReducedMotion()) {
       x.jump(next.x)
       width.jump(next.width)
       setReady(true)
diff --git a/packages/ui/src/overlays/tooltip/tooltip.css b/packages/ui/src/overlays/tooltip/tooltip.css
index 8c03633e128..cdd8a0b98f9 100644
--- a/packages/ui/src/overlays/tooltip/tooltip.css
+++ b/packages/ui/src/overlays/tooltip/tooltip.css
@@ -94,7 +94,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="tooltip-v2"],
   [data-component="tooltip-v2"][data-closed] {
     animation: none;
diff --git a/packages/ui/src/styles/tailwind/index.css b/packages/ui/src/styles/tailwind/index.css
index 2bd4ee41b0a..ea32b40dac0 100644
--- a/packages/ui/src/styles/tailwind/index.css
+++ b/packages/ui/src/styles/tailwind/index.css
@@ -18,6 +18,10 @@
 @source not "../../../src/**/*.test.{ts,tsx}";
 @import "./utilities.css";
 
+/* The app resolves its reduce motion setting, including the system preference, into this attribute. */
+@custom-variant motion-reduce (&:where(:root[data-motion="reduce"] *));
+@custom-variant motion-safe (&:where(:root:not([data-motion="reduce"]) *));
+
 @import "../index.css";
 
 @theme {
diff --git a/packages/ui/src/typography/text-shimmer/text-shimmer.css b/packages/ui/src/typography/text-shimmer/text-shimmer.css
index 3122bf03158..ae8f08d85f3 100644
--- a/packages/ui/src/typography/text-shimmer/text-shimmer.css
+++ b/packages/ui/src/typography/text-shimmer/text-shimmer.css
@@ -101,7 +101,7 @@
   }
 }
 
-@media (prefers-reduced-motion: reduce) {
+:root[data-motion="reduce"] {
   [data-component="text-shimmer"] [data-slot="text-shimmer-char-base"],
   [data-component="text-shimmer"] [data-slot="text-shimmer-char-shimmer"] {
     transition-duration: 0ms;