diff --git a/src/lib/due.ts b/src/lib/due.ts
index b67fe67..219fd2a 100644
--- a/src/lib/due.ts
+++ b/src/lib/due.ts
@@ -29,12 +29,6 @@ export function shiftDays(key: string, days: number): string {
   return localKey(date);
 }
 
-/** Milliseconds until the next local midnight, with a little slack past it. */
-export function untilMidnight(now = new Date()): number {
-  const next = new Date(now.getFullYear(), now.getMonth(), now.getDate() + 1);
-  return Math.max(1000, next.getTime() - now.getTime() + 500);
-}
-
 export function daysFromToday(key: string, from = today()): number {
   return Math.round((fromKey(key).getTime() - fromKey(from).getTime()) / 86_400_000);
 }
diff --git a/src/vault/store.svelte.ts b/src/vault/store.svelte.ts
index aaa8fec..fff629a 100644
--- a/src/vault/store.svelte.ts
+++ b/src/vault/store.svelte.ts
@@ -4,7 +4,7 @@ import { isArchivePath, toBoardPath } from "../model/archive";
 import { parseBoard, sphereOf } from "../model/board";
 import { anchorDate, isOpen, STATUS_ORDER } from "../model/types";
 import type { Board, Status, Task } from "../model/types";
-import { daysFromToday, fromKey, localKey, shiftDays, untilMidnight } from "../lib/due";
+import { daysFromToday, fromKey, localKey, shiftDays } from "../lib/due";
 import { laneKey, parseLaneKey } from "../lib/keys";
 import type {
   BeaverCalendarSettings,
@@ -197,37 +197,35 @@ export class BoardStore {
     this.settings = settings;
   }
 
-  /** Re-reads the wall clock; a no-op while the day has not turned. */
+  /**
+   * Re-reads the wall clock; a no-op while the day has not turned. A cursor
+   * left on the old today, and a month showing it, follow the day over.
+   */
   tick(): void {
     const now = localKey(new Date());
-    if (now !== this.today) this.today = now;
+    const was = this.today;
+    if (now === was) return;
+    this.today = now;
+    if (this.cursorDay === was && this.cursorTask === null) this.cursorDay = now;
+    if (this.monthKey.slice(0, 7) === was.slice(0, 7)) this.monthKey = now;
   }
 
   /**
-   * Keeps `today` honest for as long as the view lives: a timer for the
-   * midnight crossing, and a re-read when the window wakes up, since a
-   * sleeping laptop fires no timers.
+   * Keeps `today` honest for as long as the view lives. The clock is polled
+   * rather than timed to midnight: Chromium's timers stop while a Mac sleeps,
+   * so a midnight timeout fires hours late, and a window that stayed focused
+   * through the sleep sends no focus event on waking. Waking still re-reads
+   * at once where the events do come.
    */
   watchClock(): () => void {
-    let timer = 0;
-    const arm = (): void => {
-      window.clearTimeout(timer);
-      timer = window.setTimeout(() => {
-        this.tick();
-        arm();
-      }, untilMidnight());
-    };
-    const wake = (): void => {
-      this.tick();
-      arm();
-    };
-    arm();
-    window.addEventListener("focus", wake);
-    document.addEventListener("visibilitychange", wake);
+    const tick = (): void => this.tick();
+    const timer = window.setInterval(tick, 30_000);
+    window.addEventListener("focus", tick);
+    document.addEventListener("visibilitychange", tick);
     return () => {
-      window.clearTimeout(timer);
-      window.removeEventListener("focus", wake);
-      document.removeEventListener("visibilitychange", wake);
+      window.clearInterval(timer);
+      window.removeEventListener("focus", tick);
+      document.removeEventListener("visibilitychange", tick);
     };
   }
 
diff --git a/tests/due.test.ts b/tests/due.test.ts
index 618aace..76fd8fd 100644
--- a/tests/due.test.ts
+++ b/tests/due.test.ts
@@ -4,7 +4,6 @@ import {
   dueLabel,
   dueTone,
   nextFriday,
-  untilMidnight,
 } from "../src/lib/due";
 
 describe("due helpers read the day they are given", () => {
@@ -26,12 +25,4 @@ describe("due helpers read the day they are given", () => {
     expect(nextFriday("2026-08-23")).toBe("2026-08-28");
     expect(nextFriday("2026-08-28")).toBe("2026-09-04");
   });
-
-  it("arms the midnight timer for the coming midnight", () => {
-    const late = new Date(2026, 7, 23, 23, 59, 0);
-    expect(untilMidnight(late)).toBeGreaterThan(60_000);
-    expect(untilMidnight(late)).toBeLessThan(62_000);
-    const early = new Date(2026, 7, 23, 0, 0, 1);
-    expect(untilMidnight(early)).toBeGreaterThan(23 * 3_600_000);
-  });
 });