From aafd8b6bf77a3e8fc1ae6dc202aa83caa46ed4fa Mon Sep 17 00:00:00 2001
From: syuilo <4439005+syuilo@users.noreply.github.com>
Date: Wed, 22 Oct 2025 09:11:15 +0900
Subject: [PATCH] =?UTF-8?q?fix(frontend):=20=E3=83=80=E3=83=BC=E3=82=AF?=
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Fix #16688
---
 CHANGELOG.md                         |  1 +
 packages/frontend/src/boot/common.ts | 10 +---------
 packages/frontend/src/theme.ts       |  7 +++----
 3 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9da1baab43..2e0957a145 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@
   - ウォーターマークを敷き詰めると上下左右反転した画像/文字が表示される問題を修正
   - ウォーターマークを回転させた際に画面からはみ出た部分を考慮できるように
 - Fix: 投票が終了した後に投票結果が正しく表示されない問題を修正
+- Fix: ダークモードの同期が機能しない場合がある問題を修正
 
 ### Server
 - Enhance: 管理者/モデレーターはファイルのアップロード制限をバイパスするように
diff --git a/packages/frontend/src/boot/common.ts b/packages/frontend/src/boot/common.ts
index 4becf32ab5..95ba278ff4 100644
--- a/packages/frontend/src/boot/common.ts
+++ b/packages/frontend/src/boot/common.ts
@@ -176,7 +176,7 @@ export async function common(createVue: () => Promise<App<Element>>) {
 		})();
 
 		applyTheme(theme);
-	}, { immediate: isSafeMode || miLocalStorage.getItem('theme') == null });
+	}, { immediate: true });
 
 	window.document.documentElement.dataset.colorScheme = store.s.darkMode ? 'dark' : 'light';
 
@@ -195,14 +195,6 @@ export async function common(createVue: () => Promise<App<Element>>) {
 				applyTheme(theme ?? defaultLightTheme);
 			}
 		});
-	}
-
-	if (!isSafeMode) {
-		if (prefer.s.darkTheme && store.s.darkMode) {
-			if (miLocalStorage.getItem('themeId') !== prefer.s.darkTheme.id) applyTheme(prefer.s.darkTheme);
-		} else if (prefer.s.lightTheme && !store.s.darkMode) {
-			if (miLocalStorage.getItem('themeId') !== prefer.s.lightTheme.id) applyTheme(prefer.s.lightTheme);
-		}
 
 		fetchInstanceMetaPromise.then(() => {
 			// TODO: instance.defaultLightTheme/instance.defaultDarkThemeが不正な形式だった場合のケア
diff --git a/packages/frontend/src/theme.ts b/packages/frontend/src/theme.ts
index 4d03b1d0e9..7cbaf87243 100644
--- a/packages/frontend/src/theme.ts
+++ b/packages/frontend/src/theme.ts
@@ -131,7 +131,7 @@ function applyThemeInternal(theme: Theme, persist: boolean) {
 }
 
 let timeout: number | null = null;
-let currentTheme: Theme | null = null;
+let currentThemeId = miLocalStorage.getItem('themeId');
 
 export function applyTheme(theme: Theme, persist = true) {
 	if (timeout) {
@@ -139,9 +139,8 @@ export function applyTheme(theme: Theme, persist = true) {
 		timeout = null;
 	}
 
-	if (deepEqual(currentTheme, theme)) return;
-	// リアクティビティ解除
-	currentTheme = deepClone(theme);
+	if (theme.id === currentThemeId) return;
+	currentThemeId = theme.id;
 
 	if (window.document.startViewTransition != null) {
 		window.document.documentElement.classList.add('_themeChanging_');