diff --git a/web/src/components/UndoToast.test.ts b/web/src/components/UndoToast.test.ts
new file mode 100644
index 0000000..3378504
--- /dev/null
+++ b/web/src/components/UndoToast.test.ts
@@ -0,0 +1,74 @@
+import { mount } from '@vue/test-utils'
+import UndoToast from './UndoToast.vue'
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
+
+// Mock requestAnimationFrame for jsdom
+beforeEach(() => {
+  vi.stubGlobal('requestAnimationFrame', (fn: FrameRequestCallback) => {
+    // Call with a fake timestamp to simulate one frame
+    setTimeout(() => fn(16), 0)
+    return 1
+  })
+  vi.stubGlobal('cancelAnimationFrame', vi.fn())
+})
+
+afterEach(() => {
+  vi.unstubAllGlobals()
+})
+
+const labelAction = {
+  type: 'label' as const,
+  item: { id: 'abc', subject: 'Interview at Acme', body: '...', from: 'hr@acme.com', date: '2026-03-01', source: 'imap:test' },
+  label: 'interview_scheduled',
+}
+
+const skipAction = {
+  type: 'skip' as const,
+  item: { id: 'xyz', subject: 'Cold Outreach', body: '...', from: 'recruiter@x.com', date: '2026-03-01', source: 'imap:test' },
+}
+
+const discardAction = {
+  type: 'discard' as const,
+  item: { id: 'def', subject: 'Spam Email', body: '...', from: 'spam@spam.com', date: '2026-03-01', source: 'imap:test' },
+}
+
+describe('UndoToast', () => {
+  it('renders subject for a label action', () => {
+    const w = mount(UndoToast, { props: { action: labelAction } })
+    expect(w.text()).toContain('Interview at Acme')
+    expect(w.text()).toContain('interview_scheduled')
+  })
+
+  it('renders subject for a skip action', () => {
+    const w = mount(UndoToast, { props: { action: skipAction } })
+    expect(w.text()).toContain('Cold Outreach')
+    expect(w.text()).toContain('Skipped')
+  })
+
+  it('renders subject for a discard action', () => {
+    const w = mount(UndoToast, { props: { action: discardAction } })
+    expect(w.text()).toContain('Spam Email')
+    expect(w.text()).toContain('Discarded')
+  })
+
+  it('has undo button', () => {
+    const w = mount(UndoToast, { props: { action: labelAction } })
+    expect(w.find('.undo-btn').exists()).toBe(true)
+  })
+
+  it('emits undo when button clicked', async () => {
+    const w = mount(UndoToast, { props: { action: labelAction } })
+    await w.find('.undo-btn').trigger('click')
+    expect(w.emitted('undo')).toBeTruthy()
+  })
+
+  it('has timer bar element', () => {
+    const w = mount(UndoToast, { props: { action: labelAction } })
+    expect(w.find('.timer-bar').exists()).toBe(true)
+  })
+
+  it('has accessible role=status', () => {
+    const w = mount(UndoToast, { props: { action: labelAction } })
+    expect(w.find('[role="status"]').exists()).toBe(true)
+  })
+})
diff --git a/web/src/components/UndoToast.vue b/web/src/components/UndoToast.vue
new file mode 100644
index 0000000..18e7f57
--- /dev/null
+++ b/web/src/components/UndoToast.vue
@@ -0,0 +1,105 @@
+<template>
+  <div class="undo-toast" role="status" aria-live="polite">
+    <span class="toast-label">{{ label }}</span>
+    <button class="undo-btn" @click="$emit('undo')">↩ Undo</button>
+    <div class="timer-track" aria-hidden="true">
+      <div class="timer-bar" :style="{ width: `${progress}%` }" />
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { ref, onMounted, onUnmounted, computed } from 'vue'
+import type { LastAction } from '../stores/label'
+
+const props = defineProps<{ action: LastAction }>()
+defineEmits<{ undo: [] }>()
+
+const DURATION = 5000
+const elapsed  = ref(0)
+let start = 0
+let raf = 0
+
+const progress = computed(() => Math.max(0, 100 - (elapsed.value / DURATION) * 100))
+
+const label = computed(() => {
+  const name = props.action.item.subject
+  if (props.action.type === 'label')   return `Labeled "${name}" as ${props.action.label}`
+  if (props.action.type === 'discard') return `Discarded "${name}"`
+  return `Skipped "${name}"`
+})
+
+function tick(ts: number) {
+  if (!start) start = ts
+  elapsed.value = ts - start
+  if (elapsed.value < DURATION) {
+    raf = requestAnimationFrame(tick)
+  }
+}
+
+onMounted(()   => { raf = requestAnimationFrame(tick) })
+onUnmounted(() => cancelAnimationFrame(raf))
+</script>
+
+<style scoped>
+.undo-toast {
+  position: fixed;
+  bottom: 1.5rem;
+  left: 50%;
+  transform: translateX(-50%);
+  min-width: 280px;
+  max-width: 480px;
+  background: var(--color-surface-overlay, #1a2338);
+  color: var(--color-text-inverse, #f0f4fc);
+  border-radius: var(--radius-toast, 0.75rem);
+  padding: 0.75rem 1rem 0;
+  display: flex;
+  align-items: center;
+  gap: 0.75rem;
+  box-shadow: 0 4px 24px rgba(0,0,0,0.25);
+  z-index: 1000;
+}
+
+.toast-label {
+  flex: 1;
+  font-size: 0.9rem;
+  font-family: var(--font-body, sans-serif);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.undo-btn {
+  flex-shrink: 0;
+  padding: 0.3rem 0.75rem;
+  border-radius: 0.375rem;
+  border: 1px solid var(--app-primary, #5A9DBF);
+  background: transparent;
+  color: var(--app-primary, #5A9DBF);
+  font-size: 0.85rem;
+  cursor: pointer;
+  transition: background 0.15s, color 0.15s;
+  margin-bottom: 0.75rem;
+}
+.undo-btn:hover {
+  background: var(--app-primary, #5A9DBF);
+  color: #fff;
+}
+
+.timer-track {
+  position: absolute;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  height: 3px;
+  background: rgba(255,255,255,0.15);
+  border-radius: 0 0 0.75rem 0.75rem;
+  overflow: hidden;
+}
+
+.timer-bar {
+  height: 100%;
+  background: var(--app-primary, #5A9DBF);
+  transition: width 0.1s linear;
+}
+</style>