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diff --git a/openless-all/app/src-tauri/src/persistence/history.rs b/openless-all/app/src-tauri/src/persistence/history.rs
index 0e50792f..2778a9c5 100644
--- a/openless-all/app/src-tauri/src/persistence/history.rs
+++ b/openless-all/app/src-tauri/src/persistence/history.rs
@@ -1,12 +1,12 @@
 #![cfg_attr(target_os = "linux", allow(dead_code, unused_variables))]
-//! Dictation history store: newest-first JSON list with retention + count caps.
+//! Dictation history store: newest-first JSON list with optional retention + count caps.
 
 use std::path::PathBuf;
 
 use anyhow::{Context, Result};
 use parking_lot::Mutex;
 
-use super::{atomic_write, data_dir, ensure_dir, read_or_default, HISTORY_CAP};
+use super::{atomic_write, data_dir, ensure_dir, read_or_default};
 use crate::types::DictationSession;
 
 const HISTORY_FILE: &str = "history.json";
@@ -43,9 +43,7 @@ impl HistoryStore {
 
     /// `retention_days == 0` 跟旧 append 行为一致（不按时间清理）。
     /// `> 0` 时在写入新条目后顺手把超过 N 天的会话裁掉，写入时就完成清理，
-    /// 不需要后台轮询。最后再受条数上限约束：
-    /// - `max_entries == None` → HISTORY_CAP (200)
-    /// - `max_entries == Some(n)` → clamp 到 5..=HISTORY_CAP，避免用户填 0 / 极大值。
+    /// 不需要后台轮询。`max_entries == None` 时不按条数裁剪。
     pub fn append_with_retention(
         &self,
         session: DictationSession,
@@ -65,11 +63,11 @@ impl HistoryStore {
                     .unwrap_or(true)
             });
         }
-        let cap = max_entries
-            .map(|n| (n as usize).clamp(5, HISTORY_CAP))
-            .unwrap_or(HISTORY_CAP);
-        if sessions.len() > cap {
-            sessions.truncate(cap);
+        if let Some(max_entries) = max_entries {
+            let cap = (max_entries as usize).max(1);
+            if sessions.len() > cap {
+                sessions.truncate(cap);
+            }
         }
         self.write_locked(&sessions)
     }
@@ -133,3 +131,50 @@ impl HistoryStore {
         atomic_write(&self.path, &json)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::HistoryStore;
+    use crate::types::{DictationSession, InsertStatus, PolishMode};
+    use parking_lot::Mutex;
+
+    fn session(id: usize) -> DictationSession {
+        DictationSession {
+            id: format!("session-{id}"),
+            created_at: "2026-01-01T00:00:00Z".into(),
+            raw_transcript: String::new(),
+            final_text: format!("text {id}"),
+            mode: PolishMode::Light,
+            style_pack_id: None,
+            translation_active: false,
+            polish_source: None,
+            app_bundle_id: None,
+            app_name: None,
+            insert_status: InsertStatus::Inserted,
+            error_code: None,
+            duration_ms: Some(1000),
+            dictionary_entry_count: None,
+            has_audio_recording: None,
+        }
+    }
+
+    #[test]
+    fn append_with_no_max_entries_keeps_more_than_legacy_cap() {
+        let dir =
+            std::env::temp_dir().join(format!("openless-history-test-{}", uuid::Uuid::new_v4()));
+        std::fs::create_dir_all(&dir).expect("create temp dir");
+        let store = HistoryStore {
+            path: dir.join("history.json"),
+            lock: Mutex::new(()),
+        };
+
+        for id in 0..205 {
+            store
+                .append_with_retention(session(id), 0, None)
+                .expect("append session");
+        }
+
+        assert_eq!(store.list().expect("list history").len(), 205);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}
diff --git a/openless-all/app/src-tauri/src/persistence/preferences.rs b/openless-all/app/src-tauri/src/persistence/preferences.rs
index 1f3fbb4a..e03d113a 100644
--- a/openless-all/app/src-tauri/src/persistence/preferences.rs
+++ b/openless-all/app/src-tauri/src/persistence/preferences.rs
@@ -1,6 +1,6 @@
 #![cfg_attr(target_os = "linux", allow(dead_code, unused_variables))]
 //! User preferences store: a single JSON document held in memory behind a lock,
-//! with a one-time `streamingInsert` default migration on load.
+//! with one-time default migrations on load.
 
 use std::fs;
 use std::path::{Path, PathBuf};
@@ -25,22 +25,31 @@ fn read_preferences(path: &Path) -> Result<UserPreferences> {
     // issue #440：老版本可能已把旧默认 `streamingInsert:false` 写进 preferences.json。
     // 反序列化会在内存里迁到 true，但还必须把迁移标记落盘，否则每次启动都停留在
     // “旧文件”状态，无法表达用户后续手动关闭后的 durable opt-out。
-    let streaming_default_migrated = serde_json::from_slice::<serde_json::Value>(&bytes)
-        .ok()
+    let raw = serde_json::from_slice::<serde_json::Value>(&bytes).ok();
+    let streaming_default_migrated = raw
+        .as_ref()
         .and_then(|value| {
             value
                 .get("streamingInsertDefaultMigrated")
                 .and_then(|flag| flag.as_bool())
         })
         .unwrap_or(false);
-    if !streaming_default_migrated {
+    let history_retention_default_migrated = raw
+        .as_ref()
+        .and_then(|value| {
+            value
+                .get("historyRetentionDefaultMigrated")
+                .and_then(|flag| flag.as_bool())
+        })
+        .unwrap_or(false);
+    if !streaming_default_migrated || !history_retention_default_migrated {
         match serde_json::to_vec_pretty(&prefs)
             .context("encode prefs failed")
             .and_then(|json| atomic_write(path, &json))
         {
-            Ok(()) => log::info!("[prefs] migrated streamingInsert default marker"),
+            Ok(()) => log::info!("[prefs] migrated preferences default markers"),
             Err(err) => log::warn!(
-                "[prefs] failed to persist streamingInsert migration marker for {}: {}",
+                "[prefs] failed to persist preferences migration markers for {}: {}",
                 path.display(),
                 err
             ),
@@ -123,6 +132,7 @@ mod tests {
         let prefs = read_preferences(&path).expect("read prefs");
         assert!(prefs.streaming_insert);
         assert!(prefs.streaming_insert_default_migrated);
+        assert!(prefs.history_retention_default_migrated);
 
         let saved: serde_json::Value =
             serde_json::from_slice(&fs::read(&path).expect("read saved prefs"))
@@ -142,4 +152,44 @@ mod tests {
 
         let _ = fs::remove_dir_all(&tmp);
     }
+
+    #[test]
+    fn legacy_history_retention_default_is_migrated_to_unlimited() {
+        let tmp: PathBuf = std::env::temp_dir().join(format!(
+            "openless-history-retention-prefs-test-{}",
+            uuid::Uuid::new_v4()
+        ));
+        fs::create_dir_all(&tmp).expect("create temp dir");
+        let path = tmp.join("preferences.json");
+        fs::write(
+            &path,
+            r#"{
+                "historyRetentionDays": 7,
+                "streamingInsertDefaultMigrated": true
+            }"#,
+        )
+        .expect("write legacy prefs");
+
+        let prefs = read_preferences(&path).expect("read prefs");
+        assert_eq!(prefs.history_retention_days, 0);
+        assert!(prefs.history_retention_default_migrated);
+
+        let saved: serde_json::Value =
+            serde_json::from_slice(&fs::read(&path).expect("read saved prefs"))
+                .expect("decode saved prefs");
+        assert_eq!(
+            saved
+                .get("historyRetentionDays")
+                .and_then(|value| value.as_u64()),
+            Some(0)
+        );
+        assert_eq!(
+            saved
+                .get("historyRetentionDefaultMigrated")
+                .and_then(|value| value.as_bool()),
+            Some(true)
+        );
+
+        let _ = fs::remove_dir_all(&tmp);
+    }
 }
diff --git a/openless-all/app/src-tauri/src/types.rs b/openless-all/app/src-tauri/src/types.rs
index 3348ee0e..54ef48cf 100644
--- a/openless-all/app/src-tauri/src/types.rs
+++ b/openless-all/app/src-tauri/src/types.rs
@@ -712,10 +712,14 @@ pub struct UserPreferences {
     /// 一个手动下载 Beta 的入口。不影响 plugin-updater 的自动检查路径。
     #[serde(default)]
     pub update_channel: UpdateChannel,
-    /// 历史记录保留天数。0 = 不按时间清理（仅受 200 条上限）。默认 7 天。
+    /// 历史记录保留天数。0 = 不按时间清理（仅受 200 条上限）。默认 0（不限天数）。
     /// 写入新条目时执行清理，避免后台轮询。
     #[serde(default = "default_history_retention_days")]
     pub history_retention_days: u32,
+    /// 老版本会把默认 7 天写进 preferences.json。缺少此标记且值仍为 7 时，
+    /// 升级后迁到 0（不限）；用户显式设置的其他天数保留。
+    #[serde(default)]
+    pub history_retention_default_migrated: bool,
     /// 对话感知 polish 的上下文窗口（分钟）：把最近 N 分钟的转写 + 已润色文本
     /// 作为多轮上下文喂给 LLM，让代词 / 不完整句子能被正确解析。
     /// 0 = 关闭（每次润色独立单轮，跟历史行为一致）。默认 5 分钟。
@@ -729,6 +733,9 @@ pub struct UserPreferences {
     /// UI theme: follow OS, force light, or force dark. Frontend applies via data-ol-theme.
     #[serde(default)]
     pub theme_mode: ThemeMode,
+    /// Whether the Overview page shows the annual activity heatmap. Default true.
+    #[serde(default = "default_true")]
+    pub show_overview_activity_heatmap: bool,
     /// 流式输入：润色 SSE 一边到达一边逐字模拟键盘事件输出到当前焦点。开启后用户感知到
     /// 的处理时延显著降低（润色 LLM 第一个 token 即开始落字）。
     ///
@@ -762,8 +769,8 @@ pub struct UserPreferences {
     /// 用户在 Settings → 关于 里可关。关闭后仅手动「检查更新」按钮可用。
     #[serde(default = "default_true")]
     pub auto_update_check: bool,
-    /// 历史记录上限（条数）。`None` = 使用代码内 200 条硬上限；
-    /// `Some(n)` 表示用户在 Settings 自定义了上限（5..=200 之间）。
+    /// 历史记录上限（条数）。`None` = 不按条数清理；
+    /// `Some(n)` 表示用户在 Settings 自定义了上限。
     #[serde(default)]
     pub history_max_entries: Option<u32>,
     /// 是否为每次会话保留原始麦克风音频文件（wav）到 `recordings/` 目录，
@@ -818,7 +825,7 @@ fn default_remote_input_mode() -> String {
 }
 
 fn default_history_retention_days() -> u32 {
-    7
+    0
 }
 
 fn default_polish_context_window_minutes() -> u32 {
@@ -946,6 +953,8 @@ struct UserPreferencesWire {
     update_channel: UpdateChannel,
     #[serde(default = "default_history_retention_days")]
     history_retention_days: u32,
+    #[serde(default)]
+    history_retention_default_migrated: bool,
     #[serde(default = "default_polish_context_window_minutes")]
     polish_context_window_minutes: u32,
     #[serde(default)]
@@ -953,6 +962,8 @@ struct UserPreferencesWire {
     #[serde(default)]
     theme_mode: ThemeMode,
     #[serde(default = "default_true")]
+    show_overview_activity_heatmap: bool,
+    #[serde(default = "default_true")]
     streaming_insert: bool,
     #[serde(default)]
     streaming_insert_default_migrated: bool,
@@ -1042,9 +1053,11 @@ impl Default for UserPreferencesWire {
             sherpa_onnx_keep_loaded_secs: prefs.sherpa_onnx_keep_loaded_secs,
             update_channel: prefs.update_channel,
             history_retention_days: prefs.history_retention_days,
+            history_retention_default_migrated: prefs.history_retention_default_migrated,
             polish_context_window_minutes: prefs.polish_context_window_minutes,
             start_minimized: prefs.start_minimized,
             theme_mode: prefs.theme_mode,
+            show_overview_activity_heatmap: prefs.show_overview_activity_heatmap,
             streaming_insert: prefs.streaming_insert,
             streaming_insert_default_migrated: prefs.streaming_insert_default_migrated,
             streaming_insert_save_clipboard: prefs.streaming_insert_save_clipboard,
@@ -1081,6 +1094,13 @@ impl<'de> Deserialize<'de> for UserPreferences {
         } else {
             true
         };
+        let history_retention_default_migrated = wire.history_retention_default_migrated;
+        let history_retention_days =
+            if !history_retention_default_migrated && wire.history_retention_days == 7 {
+                0
+            } else {
+                wire.history_retention_days
+            };
 
         Ok(Self {
             hotkey: wire.hotkey,
@@ -1148,10 +1168,12 @@ impl<'de> Deserialize<'de> for UserPreferences {
             sherpa_onnx_language_hint: wire.sherpa_onnx_language_hint,
             sherpa_onnx_keep_loaded_secs: wire.sherpa_onnx_keep_loaded_secs,
             update_channel: wire.update_channel,
-            history_retention_days: wire.history_retention_days,
+            history_retention_days,
+            history_retention_default_migrated: true,
             polish_context_window_minutes: wire.polish_context_window_minutes,
             start_minimized: wire.start_minimized,
             theme_mode: wire.theme_mode,
+            show_overview_activity_heatmap: wire.show_overview_activity_heatmap,
             streaming_insert,
             streaming_insert_default_migrated: true,
             streaming_insert_save_clipboard: wire.streaming_insert_save_clipboard,
@@ -1884,9 +1906,11 @@ impl Default for UserPreferences {
             sherpa_onnx_keep_loaded_secs: default_local_asr_keep_loaded_secs(),
             update_channel: UpdateChannel::default(),
             history_retention_days: default_history_retention_days(),
+            history_retention_default_migrated: true,
             polish_context_window_minutes: default_polish_context_window_minutes(),
             start_minimized: false,
             theme_mode: ThemeMode::default(),
+            show_overview_activity_heatmap: true,
             streaming_insert: true,
             streaming_insert_default_migrated: true,
             streaming_insert_save_clipboard: true,
diff --git a/openless-all/app/src/i18n/en.ts b/openless-all/app/src/i18n/en.ts
index fcf71ca3..29106a91 100644
--- a/openless-all/app/src/i18n/en.ts
+++ b/openless-all/app/src/i18n/en.ts
@@ -26,8 +26,10 @@ export const en: typeof zhCN = {
     copied: 'Copied',
     operationFailed: 'Operation failed',
     add: 'Add',
+    unlimited: 'Unlimited',
     durationSeconds: '{{value}}s',
-    durationMinutes: '{{value}}m',
+    durationMinutes: '{{value}}min',
+    durationHours: '{{value}}h',
   },
   capsule: {
     thinking: 'thinking',
@@ -277,9 +279,25 @@ export const en: typeof zhCN = {
     metricNoData: 'No data',
     historyLoadError: 'History load failed',
     metricTotal: 'Total records',
-    metricTotalTrend: 'Local archive (max 200)',
+    metricTotalTrend: 'Local archive',
     weekTitle: 'Last 7 days',
     weekUnit: 'count / day',
+    activityTitle: 'Annual activity',
+    activityModeDaily: 'Daily',
+    activityMode: {
+      daily: 'Daily',
+      weekly: 'Weekly',
+      cumulative: 'Total',
+    },
+    activityUnit: 'Past year · {{days}} active days',
+    activityEmpty: 'No history in the past year.',
+    activityTooltip: '{{date}} · {{count}} records · {{chars}} chars',
+    activitySummaryDaily: '{{date}} used {{count}} records / {{chars}} chars / {{duration}}',
+    activitySummaryWeekly: 'Week of {{start}} used {{count}} records / {{chars}} chars / {{duration}}',
+    activitySummaryCumulative: 'Through week of {{start}} used {{count}} records / {{chars}} chars / {{duration}}',
+    activityLegendLow: 'Less',
+    activityLegendHigh: 'More',
+    monthNames: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
     recentTitle: 'Recent transcripts',
     recentAll: 'View all →',
     recentEmpty: 'No records yet. Press {{trigger}} to start your first recording.',
@@ -686,9 +704,9 @@ export const en: typeof zhCN = {
       allowNonTsfFallbackDesc: 'Windows: when TSF insertion fails, use paced Unicode SendInput; if that still fails, copy the text to the clipboard.',
       historyGroupTitle: 'History & context',
       historyRetentionLabel: 'History retention (days)',
-      historyRetentionDesc: 'Entries older than this are pruned on new writes; 0 = no time-based pruning.',
+      historyRetentionDesc: 'Entries older than this are pruned on new writes; 0 / blank = no time-based pruning.',
       historyMaxEntriesLabel: 'Max history entries',
-      historyMaxEntriesDesc: 'Max sessions retained locally. Blank = 200. Range 5–200.',
+      historyMaxEntriesDesc: 'Max sessions retained locally. 0 / blank = no count-based pruning.',
       polishContextWindowLabel: 'Polish context window (minutes)',
       polishContextWindowDesc: 'Use the last N minutes of polished transcripts as multi-turn context; 0 = disabled.',
       recordAudioForDebugLabel: 'Keep raw recording (debug)',
@@ -966,6 +984,8 @@ export const en: typeof zhCN = {
       system: 'Follow system',
       light: 'Light',
       dark: 'Dark',
+      overviewActivityLabel: 'Show overview activity heatmap',
+      overviewActivityDesc: 'Show the daily / weekly / cumulative activity heatmap at the bottom of Overview. Turning this off does not delete history.',
     },
     remoteInput: {
       title: 'Remote Input',
diff --git a/openless-all/app/src/i18n/ja.ts b/openless-all/app/src/i18n/ja.ts
index 257bfb7f..f240d8a5 100644
--- a/openless-all/app/src/i18n/ja.ts
+++ b/openless-all/app/src/i18n/ja.ts
@@ -28,8 +28,10 @@ export const ja: typeof zhCN = {
     copied: 'コピーしました',
     operationFailed: '操作に失敗しました',
     add: '追加',
-    durationSeconds: '{{value}} 秒',
-    durationMinutes: '{{value}} 分',
+    unlimited: '無制限',
+    durationSeconds: '{{value}}s',
+    durationMinutes: '{{value}}min',
+    durationHours: '{{value}}h',
   },
   capsule: {
     thinking: 'thinking',
@@ -279,9 +281,25 @@ export const ja: typeof zhCN = {
     metricNoData: 'データなし',
     historyLoadError: '履歴の読み込みに失敗',
     metricTotal: '累計記録',
-    metricTotalTrend: 'ローカル保存（上限 200）',
+    metricTotalTrend: 'ローカル保存',
     weekTitle: '直近 7 日',
     weekUnit: '件 / 日',
+    activityTitle: '年間アクティビティ',
+    activityModeDaily: '毎日',
+    activityMode: {
+      daily: '毎日',
+      weekly: '毎週',
+      cumulative: '累計',
+    },
+    activityUnit: '過去 1 年 · {{days}} 日に記録',
+    activityEmpty: '過去 1 年の履歴はまだありません。',
+    activityTooltip: '{{date}} · {{count}} 件 · {{chars}} 文字',
+    activitySummaryDaily: '{{date}} に {{count}} 件 / {{chars}} 文字 / {{duration}}',
+    activitySummaryWeekly: '{{start}} の週に {{count}} 件 / {{chars}} 文字 / {{duration}}',
+    activitySummaryCumulative: '{{start}} の週まで累計 {{count}} 件 / {{chars}} 文字 / {{duration}}',
+    activityLegendLow: '少',
+    activityLegendHigh: '多',
+    monthNames: ['1月', '2月', '3月', '4月', '5月', '6月', '7月', '8月', '9月', '10月', '11月', '12月'],
     recentTitle: '最近の認識',
     recentAll: 'すべて表示 →',
     recentEmpty: '記録がありません。{{trigger}} を押して最初の録音を始めましょう。',
@@ -688,9 +706,9 @@ export const ja: typeof zhCN = {
       allowNonTsfFallbackDesc: 'Windows：TSF 入力が失敗した時は分割した Unicode SendInput を使い、それも失敗した場合はクリップボードへコピーします。',
       historyGroupTitle: '履歴とコンテキスト',
       historyRetentionLabel: '履歴保持期間（日）',
-      historyRetentionDesc: '保持日数を超えた履歴は新規書き込み時に削除されます。0 = 時間で削除しない。',
+      historyRetentionDesc: '保持日数を超えた履歴は新規書き込み時に削除されます。0 / 空欄 = 時間で削除しない。',
       historyMaxEntriesLabel: '履歴件数の上限',
-      historyMaxEntriesDesc: 'ローカル保持セッション上限。空欄 = 200。範囲 5–200。',
+      historyMaxEntriesDesc: 'ローカル保持セッション上限。0 / 空欄 = 件数で削除しない。',
       polishContextWindowLabel: '会話コンテキスト窓（分）',
       polishContextWindowDesc: '直近 N 分間の整文済み転写をマルチターン文脈として渡します。0 = 無効。',
       recordAudioForDebugLabel: '元の録音を保持（デバッグ）',
@@ -934,6 +952,8 @@ export const ja: typeof zhCN = {
       system: 'システムに従う',
       light: 'ライト',
       dark: 'ダーク',
+      overviewActivityLabel: '概要の活動ヒートマップを表示',
+      overviewActivityDesc: '今日の概要の下部に日別 / 週別 / 累計の活動ヒートマップを表示します。オフにしても履歴は削除されません。',
     },
     remoteInput: {
       title: 'リモート入力',
diff --git a/openless-all/app/src/i18n/ko.ts b/openless-all/app/src/i18n/ko.ts
index 395f92e1..b7dd9408 100644
--- a/openless-all/app/src/i18n/ko.ts
+++ b/openless-all/app/src/i18n/ko.ts
@@ -28,8 +28,10 @@ export const ko: typeof zhCN = {
     copied: '복사됨',
     operationFailed: '작업 실패',
     add: '추가',
-    durationSeconds: '{{value}}초',
-    durationMinutes: '{{value}}분',
+    unlimited: '무제한',
+    durationSeconds: '{{value}}s',
+    durationMinutes: '{{value}}min',
+    durationHours: '{{value}}h',
   },
   capsule: {
     thinking: 'thinking',
@@ -279,9 +281,25 @@ export const ko: typeof zhCN = {
     metricNoData: '데이터 없음',
     historyLoadError: '기록 로드 실패',
     metricTotal: '누적 기록',
-    metricTotalTrend: '로컬 보관(상한 200)',
+    metricTotalTrend: '로컬 보관',
     weekTitle: '최근 7일',
     weekUnit: '건/일',
+    activityTitle: '연간 활동',
+    activityModeDaily: '매일',
+    activityMode: {
+      daily: '매일',
+      weekly: '매주',
+      cumulative: '누적',
+    },
+    activityUnit: '지난 1년 · {{days}}일 기록 있음',
+    activityEmpty: '지난 1년 동안 기록이 없습니다.',
+    activityTooltip: '{{date}} · {{count}}건 · {{chars}}자',
+    activitySummaryDaily: '{{date}} 사용 {{count}}건 / {{chars}}자 / {{duration}}',
+    activitySummaryWeekly: '{{start}} 주간 사용 {{count}}건 / {{chars}}자 / {{duration}}',
+    activitySummaryCumulative: '{{start}} 주까지 누적 사용 {{count}}건 / {{chars}}자 / {{duration}}',
+    activityLegendLow: '적음',
+    activityLegendHigh: '많음',
+    monthNames: ['1월', '2월', '3월', '4월', '5월', '6월', '7월', '8월', '9월', '10월', '11월', '12월'],
     recentTitle: '최근 인식',
     recentAll: '전체 보기 →',
     recentEmpty: '아직 기록이 없습니다. {{trigger}} 를 눌러 첫 녹음을 시작하세요.',
@@ -688,9 +706,9 @@ export const ko: typeof zhCN = {
       allowNonTsfFallbackDesc: 'Windows: TSF 입력이 실패하면 분할된 Unicode SendInput을 사용하고, 그래도 실패하면 텍스트를 클립보드에 복사합니다.',
       historyGroupTitle: '기록 및 컨텍스트',
       historyRetentionLabel: '기록 보관 기간(일)',
-      historyRetentionDesc: '보관 기간을 초과한 기록은 새 항목 작성 시 정리됩니다. 0 = 시간 기반 정리 비활성화.',
+      historyRetentionDesc: '보관 기간을 초과한 기록은 새 항목 작성 시 정리됩니다. 0 / 빈칸 = 시간 기반 정리 비활성화.',
       historyMaxEntriesLabel: '기록 개수 상한',
-      historyMaxEntriesDesc: '로컬 보관 세션 상한. 빈칸 = 200. 범위 5–200.',
+      historyMaxEntriesDesc: '로컬 보관 세션 상한. 0 / 빈칸 = 개수 기반 정리 비활성화.',
       polishContextWindowLabel: '대화 컨텍스트 윈도(분)',
       polishContextWindowDesc: '최근 N 분간 정리된 전사를 멀티턴 컨텍스트로 전달합니다. 0 = 비활성화.',
       recordAudioForDebugLabel: '원본 녹음 보관(디버그)',
@@ -934,6 +952,8 @@ export const ko: typeof zhCN = {
       system: '시스템 따르기',
       light: '라이트',
       dark: '다크',
+      overviewActivityLabel: '개요 활동 히트맵 표시',
+      overviewActivityDesc: '오늘의 개요 하단에 일별 / 주별 / 누적 활동 히트맵을 표시합니다. 꺼도 기록은 삭제되지 않습니다.',
     },
     remoteInput: {
       title: '원격 입력',
diff --git a/openless-all/app/src/i18n/zh-CN.ts b/openless-all/app/src/i18n/zh-CN.ts
index 3147b416..7ecb1abd 100644
--- a/openless-all/app/src/i18n/zh-CN.ts
+++ b/openless-all/app/src/i18n/zh-CN.ts
@@ -24,8 +24,10 @@ export const zhCN = {
     copied: '已复制',
     operationFailed: '操作失败',
     add: '添加',
-    durationSeconds: '{{value}} 秒',
-    durationMinutes: '{{value}} 分钟',
+    unlimited: '无限制',
+    durationSeconds: '{{value}}s',
+    durationMinutes: '{{value}}min',
+    durationHours: '{{value}}h',
   },
   capsule: {
     thinking: 'thinking',
@@ -275,9 +277,25 @@ export const zhCN = {
     metricNoData: '暂无数据',
     historyLoadError: '历史读取失败',
     metricTotal: '累计记录',
-    metricTotalTrend: '本机存档 (上限 200)',
+    metricTotalTrend: '本机存档',
     weekTitle: '近 7 天',
     weekUnit: '条数 / 天',
+    activityTitle: '年度活动',
+    activityModeDaily: '每日',
+    activityMode: {
+      daily: '每日',
+      weekly: '每周',
+      cumulative: '累计',
+    },
+    activityUnit: '过去一年 · {{days}} 天有记录',
+    activityEmpty: '过去一年还没有历史记录。',
+    activityTooltip: '{{date}} · {{count}} 条 · {{chars}} 字',
+    activitySummaryDaily: '{{date}} 使用了 {{count}} 条 / {{chars}} 字 / {{duration}}',
+    activitySummaryWeekly: '{{start}} 当周使用了 {{count}} 条 / {{chars}} 字 / {{duration}}',
+    activitySummaryCumulative: '截至 {{start}} 当周累计使用了 {{count}} 条 / {{chars}} 字 / {{duration}}',
+    activityLegendLow: '少',
+    activityLegendHigh: '多',
+    monthNames: ['1月', '2月', '3月', '4月', '5月', '6月', '7月', '8月', '9月', '10月', '11月', '12月'],
     recentTitle: '最近识别',
     recentAll: '全部记录 →',
     recentEmpty: '还没有记录。按 {{trigger}} 开始第一次录音。',
@@ -684,9 +702,9 @@ export const zhCN = {
       allowNonTsfFallbackDesc: 'Windows：TSF 失败时使用分批 Unicode SendInput；如果仍失败，再复制到剪贴板。',
       historyGroupTitle: '历史与上下文',
       historyRetentionLabel: '历史保留天数',
-      historyRetentionDesc: '超过保留天数的历史在写入新条目时被清理；0 = 不按时间清理。',
+      historyRetentionDesc: '超过保留天数的历史在写入新条目时被清理；0 / 留空 = 不按时间清理。',
       historyMaxEntriesLabel: '历史条数上限',
-      historyMaxEntriesDesc: '本地保留会话上限，留空 = 200。范围 5–200。',
+      historyMaxEntriesDesc: '本地保留会话上限，0 / 留空 = 不按条数清理。',
       polishContextWindowLabel: '对话上下文窗口（分钟）',
       polishContextWindowDesc: '把最近 N 分钟内已润色的转写作为多轮上下文，0 = 关闭。',
       recordAudioForDebugLabel: '保留原始录音（调试）',
@@ -964,6 +982,8 @@ export const zhCN = {
       system: '跟随系统',
       light: '浅色',
       dark: '深色',
+      overviewActivityLabel: '显示概况活动热图',
+      overviewActivityDesc: '在今日概况底部显示每日 / 每周 / 累计活动热图；关闭不会删除历史记录。',
     },
     remoteInput: {
       title: '远程输入',
diff --git a/openless-all/app/src/i18n/zh-TW.ts b/openless-all/app/src/i18n/zh-TW.ts
index 2fe58825..ca44924a 100644
--- a/openless-all/app/src/i18n/zh-TW.ts
+++ b/openless-all/app/src/i18n/zh-TW.ts
@@ -26,8 +26,10 @@ export const zhTW: typeof zhCN = {
     copied: '已複製',
     operationFailed: '操作失敗',
     add: '添加',
-    durationSeconds: '{{value}} 秒',
-    durationMinutes: '{{value}} 分鐘',
+    unlimited: '無限制',
+    durationSeconds: '{{value}}s',
+    durationMinutes: '{{value}}min',
+    durationHours: '{{value}}h',
   },
   capsule: {
     thinking: 'thinking',
@@ -277,9 +279,25 @@ export const zhTW: typeof zhCN = {
     metricNoData: '暫無數據',
     historyLoadError: '歷史讀取失敗',
     metricTotal: '累計記錄',
-    metricTotalTrend: '本機存檔 (上限 200)',
+    metricTotalTrend: '本機存檔',
     weekTitle: '近 7 天',
     weekUnit: '條數 / 天',
+    activityTitle: '年度活動',
+    activityModeDaily: '每日',
+    activityMode: {
+      daily: '每日',
+      weekly: '每週',
+      cumulative: '累計',
+    },
+    activityUnit: '過去一年 · {{days}} 天有記錄',
+    activityEmpty: '過去一年還沒有歷史記錄。',
+    activityTooltip: '{{date}} · {{count}} 條 · {{chars}} 字',
+    activitySummaryDaily: '{{date}} 使用了 {{count}} 條 / {{chars}} 字 / {{duration}}',
+    activitySummaryWeekly: '{{start}} 當週使用了 {{count}} 條 / {{chars}} 字 / {{duration}}',
+    activitySummaryCumulative: '截至 {{start}} 當週累計使用了 {{count}} 條 / {{chars}} 字 / {{duration}}',
+    activityLegendLow: '少',
+    activityLegendHigh: '多',
+    monthNames: ['1月', '2月', '3月', '4月', '5月', '6月', '7月', '8月', '9月', '10月', '11月', '12月'],
     recentTitle: '最近識別',
     recentAll: '全部記錄 →',
     recentEmpty: '還沒有記錄。按 {{trigger}} 開始第一次錄音。',
@@ -686,9 +704,9 @@ export const zhTW: typeof zhCN = {
       allowNonTsfFallbackDesc: 'Windows：TSF 失敗時使用分批 Unicode SendInput；如果仍失敗，再複製到剪貼簿。',
       historyGroupTitle: '歷史與上下文',
       historyRetentionLabel: '歷史保留天數',
-      historyRetentionDesc: '超過保留天數的歷史在寫入新條目時被清理；0 = 不按時間清理。',
+      historyRetentionDesc: '超過保留天數的歷史在寫入新條目時被清理；0 / 留空 = 不按時間清理。',
       historyMaxEntriesLabel: '歷史條數上限',
-      historyMaxEntriesDesc: '本地保留會話上限，留空 = 200。範圍 5–200。',
+      historyMaxEntriesDesc: '本地保留會話上限，0 / 留空 = 不按條數清理。',
       polishContextWindowLabel: '對話上下文窗口（分鐘）',
       polishContextWindowDesc: '把最近 N 分鐘內已潤色的轉寫作為多輪上下文，0 = 關閉。',
       recordAudioForDebugLabel: '保留原始錄音（除錯）',
@@ -932,6 +950,8 @@ export const zhTW: typeof zhCN = {
       system: '跟隨系統',
       light: '淺色',
       dark: '深色',
+      overviewActivityLabel: '顯示概況活動熱圖',
+      overviewActivityDesc: '在今日概況底部顯示每日 / 每週 / 累計活動熱圖；關閉不會刪除歷史記錄。',
     },
     remoteInput: {
       title: '遠端輸入',
diff --git a/openless-all/app/src/lib/ipc/mock-data.ts b/openless-all/app/src/lib/ipc/mock-data.ts
index 402f8cc8..1e057398 100644
--- a/openless-all/app/src/lib/ipc/mock-data.ts
+++ b/openless-all/app/src/lib/ipc/mock-data.ts
@@ -80,10 +80,12 @@ export let mockSettings: UserPreferences = {
     sherpaOnnxModel: "sense-voice-small-zh",
     sherpaOnnxLanguageHint: "",
     sherpaOnnxKeepLoadedSecs: 300,
-    historyRetentionDays: 7,
+    historyRetentionDays: 0,
+    historyRetentionDefaultMigrated: true,
     polishContextWindowMinutes: 5,
     startMinimized: false,
     themeMode: "system",
+    showOverviewActivityHeatmap: true,
     updateChannel: "stable",
     streamingInsert: true,
     streamingInsertDefaultMigrated: true,
@@ -431,23 +433,40 @@ export const mockMicrophoneDevices: MicrophoneDevice[] = [
     { name: "USB Microphone", isDefault: false },
 ]
 
-export const mockHistory: DictationSession[] = OL_DATA.history.map((h, i) => ({
-    id: `mock-${i}`,
-    createdAt: new Date().toISOString(),
-    rawTranscript: h.preview,
-    finalText: h.preview,
-    mode: "structured",
-    stylePackId: "builtin.structured",
-    translationActive: false,
-    polishSource: null,
-    appBundleId: null,
-    appName: "VS Code",
-    insertStatus: "inserted",
-    errorCode: null,
-    durationMs: 600,
-    dictionaryEntryCount: 28,
-    hasAudioRecording: null,
-}))
+const mockHistoryOffsets = [0, 0, 0, 1, 1, 2, 3, 3, 4, 5, 6, 15, 32, 54, 91, 130, 178, 230, 292, 340]
+const mockHistoryModes: PolishMode[] = ["structured", "light", "raw", "formal"]
+const mockHistoryApps = ["VS Code", "Obsidian", "Chrome", "微信", "Word"]
+
+function mockCreatedAt(dayOffset: number, index: number): string {
+    const source = OL_DATA.history[index % OL_DATA.history.length]
+    const [hours = 12, minutes = 0] = source.time.split(":").map(Number)
+    const date = new Date()
+    date.setDate(date.getDate() - dayOffset)
+    date.setHours(hours, minutes, 0, 0)
+    return date.toISOString()
+}
+
+export const mockHistory: DictationSession[] = mockHistoryOffsets.map((dayOffset, i) => {
+    const h = OL_DATA.history[i % OL_DATA.history.length]
+    const mode = mockHistoryModes[i % mockHistoryModes.length]
+    return {
+        id: `mock-${dayOffset}-${i}`,
+        createdAt: mockCreatedAt(dayOffset, i),
+        rawTranscript: h.preview,
+        finalText: h.preview,
+        mode,
+        stylePackId: `builtin.${mode}`,
+        translationActive: false,
+        polishSource: null,
+        appBundleId: null,
+        appName: mockHistoryApps[i % mockHistoryApps.length],
+        insertStatus: "inserted",
+        errorCode: null,
+        durationMs: 9000 + (i % 6) * 1800,
+        dictionaryEntryCount: 12 + (i % 5) * 4,
+        hasAudioRecording: null,
+    }
+})
 
 export const mockVocab: DictionaryEntry[] = OL_DATA.vocab.map((v, i) => ({
     id: `vocab-${i}`,
diff --git a/openless-all/app/src/lib/stylePrefs.test.ts b/openless-all/app/src/lib/stylePrefs.test.ts
index d049a4a5..b6d91643 100644
--- a/openless-all/app/src/lib/stylePrefs.test.ts
+++ b/openless-all/app/src/lib/stylePrefs.test.ts
@@ -67,10 +67,12 @@ const previousPrefs: UserPreferences = {
   sherpaOnnxModel: 'sense-voice-small-zh',
   sherpaOnnxLanguageHint: '',
   sherpaOnnxKeepLoadedSecs: 300,
-  historyRetentionDays: 7,
+  historyRetentionDays: 0,
+  historyRetentionDefaultMigrated: true,
   polishContextWindowMinutes: 5,
   startMinimized: false,
   themeMode: 'system',
+  showOverviewActivityHeatmap: true,
   updateChannel: 'stable',
   streamingInsert: true,
   streamingInsertDefaultMigrated: true,
diff --git a/openless-all/app/src/lib/types.ts b/openless-all/app/src/lib/types.ts
index fe8c8baa..e53deb74 100644
--- a/openless-all/app/src/lib/types.ts
+++ b/openless-all/app/src/lib/types.ts
@@ -325,8 +325,10 @@ export interface UserPreferences {
   sherpaOnnxLanguageHint: string;
   /** Windows sherpa-onnx 模型在 runtime 中保持加载的秒数。 */
   sherpaOnnxKeepLoadedSecs: number;
-  /** 历史记录保留天数。0 = 不按时间清理（仍受 200 条上限）。默认 7。 */
+  /** 历史记录保留天数。0 = 不按时间清理。默认 0（不限天数）。 */
   historyRetentionDays: number;
+  /** 旧默认 7 天是否已迁移到不限。 */
+  historyRetentionDefaultMigrated: boolean;
   /** 对话感知 polish 上下文窗口（分钟）。0 = 关闭。默认 5。详见 PR-A。 */
   polishContextWindowMinutes: number;
   /** 启动时静默运行（不弹主窗口）。Windows 开机自启场景常用——只想要后台 + 托盘，
@@ -334,6 +336,8 @@ export interface UserPreferences {
   startMinimized: boolean;
   /** UI theme preference: follow OS, light, or dark. */
   themeMode: ThemeMode;
+  /** Show the annual activity heatmap on the Overview page. Default true. */
+  showOverviewActivityHeatmap: boolean;
   /** 自动更新渠道。'stable'（默认）= plugin-updater 仅检查正式版；
    *  'beta' = Settings → About 出现手动下载 Beta 的入口。 */
   updateChannel: UpdateChannel;
@@ -350,7 +354,7 @@ export interface UserPreferences {
   /** 主窗口启动 + 后台每 60 分钟自动检查云端新版本。默认 true。
    *  关闭后仅 Settings → 关于 的「检查更新」手动按钮可用。 */
   autoUpdateCheck: boolean;
-  /** 历史记录上限（条数）。null = 走默认 200；5..=200 之间为用户自定义。 */
+  /** 历史记录上限（条数）。null = 不按条数清理。 */
   historyMaxEntries: number | null;
   /** 是否为每次会话保留原始麦克风音频文件（wav），用于排查 ASR 误识别 / 麦克风灵敏度。
    *  默认 false。开启后会占磁盘空间，受 historyRetentionDays 同样的清理策略约束。 */
diff --git a/openless-all/app/src/pages/Overview.tsx b/openless-all/app/src/pages/Overview.tsx
index 6e9d77ff..ff8e1c63 100644
--- a/openless-all/app/src/pages/Overview.tsx
+++ b/openless-all/app/src/pages/Overview.tsx
@@ -1,6 +1,6 @@
 // Overview.tsx — 真实指标，从 listHistory + getCredentials 派生。
 
-import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
+import { useCallback, useEffect, useMemo, useRef, useState, type PointerEvent } from 'react';
 import { useTranslation } from 'react-i18next';
 import { Icon } from '../components/Icon';
 import { formatComboLabel } from '../lib/hotkey';
@@ -52,6 +52,10 @@ const LLM_NAME_KEY_BY_ID: Record<string, string> = {
   custom: 'custom',
 };
 
+type ActivityMode = 'daily' | 'weekly' | 'cumulative';
+
+const ACTIVITY_MODES: ActivityMode[] = ['daily', 'weekly', 'cumulative'];
+
 export function Overview({ onOpenHistory }: OverviewProps) {
   const { t } = useTranslation();
   const mobile = useMobileLayout();
@@ -67,6 +71,7 @@ export function Overview({ onOpenHistory }: OverviewProps) {
     volcengineConfigured: false,
     arkConfigured: false,
   });
+  const [activityMode, setActivityMode] = useState<ActivityMode>('daily');
   const { prefs } = useHotkeySettings();
   const credentialsRequestSeq = useRef(0);
 
@@ -159,6 +164,17 @@ export function Overview({ onOpenHistory }: OverviewProps) {
     return buckets;
   }, [history]);
 
+  const monthNames = useMemo(
+    () => t('overview.monthNames', { returnObjects: true }) as string[],
+    [t],
+  );
+
+  const yearlyActivity = useMemo(
+    () => buildYearlyActivity(history, monthNames, activityMode),
+    [history, monthNames, activityMode],
+  );
+  const showActivityHeatmap = prefs?.showOverviewActivityHeatmap !== false;
+
   const asrProviderId = creds.activeAsrProvider || 'volcengine';
   const llmProviderId = creds.activeLlmProvider || 'ark';
   const asrNameKey = ASR_NAME_KEY_BY_ID[asrProviderId];
@@ -189,18 +205,16 @@ export function Overview({ onOpenHistory }: OverviewProps) {
         />
       </div>
 
-      <div className="ol-overview-hero" style={{ display: 'grid', gridTemplateColumns: mobile ? 'repeat(2, 1fr)' : 'repeat(4, 1fr)', gap: 12, marginBottom: 18 }}>
+      <div style={{ display: 'grid', gridTemplateColumns: mobile ? 'repeat(2, 1fr)' : 'repeat(4, 1fr)', gap: 12, marginBottom: 18 }}>
         <Metric icon="hash" label={t('overview.metricChars')} value={historyError ? '—' : metrics.charsToday.toLocaleString()} trend={historyError ? t('overview.historyLoadError') : t('overview.metricSegments', { count: metrics.segmentsToday })} />
         <Metric icon="mic" label={t('overview.metricDuration')} value={historyError ? '—' : formatDuration(metrics.totalDurationMs, t)} trend={historyError ? t('overview.historyLoadError') : ''} />
         <Metric icon="clock" label={t('overview.metricAvg')} value={historyError ? '—' : formatDuration(metrics.avgLatencyMs, t)} trend={historyError ? t('overview.historyLoadError') : metrics.segmentsToday > 0 ? t('overview.metricAvgTrend') : t('overview.metricNoData')} />
         <Metric icon="bolt" label={t('overview.metricTotal')} value={historyError ? '—' : String(history.length)} trend={historyError ? t('overview.historyLoadError') : t('overview.metricTotalTrend')} accent />
       </div>
 
-      {/* 底部一行 = flex:1 撑满剩余高度（父 wrapper 是 display:flex/column）。
-          只有「最近识别」内部允许滚动；其他卡片按内容自然高度，不破裂底部圆角。
-          issue #243 follow-up：去掉外层 overflow 后底部圆角被裁的视觉问题。 */}
-      <div style={{ display: 'grid', gridTemplateColumns: mobile ? '1fr' : '1fr 1.4fr', gap: 12, flex: mobile ? undefined : 1, minHeight: mobile ? undefined : 0 }}>
-        <Card padding={18} style={{ display: 'flex', flexDirection: 'column', minHeight: 0 }}>
+      {/* 近 7 天和最近识别固定一个可读高度；最近识别内部滚动，避免和年度活动互相遮挡。 */}
+      <div style={{ display: 'grid', gridTemplateColumns: mobile ? '1fr' : '1fr 1.4fr', gap: 12, flexShrink: 0, height: mobile ? undefined : 210 }}>
+        <Card padding={18} style={{ display: 'flex', flexDirection: 'column', height: mobile ? undefined : '100%', minHeight: 0, overflow: 'hidden' }}>
           <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 14 }}>
             <span style={{ fontSize: 12, fontWeight: 600, color: 'var(--ol-ink-2)' }}>{t('overview.weekTitle')}</span>
             <span style={{ fontSize: 11, color: 'var(--ol-ink-4)' }}>{t('overview.weekUnit')}</span>
@@ -212,12 +226,15 @@ export function Overview({ onOpenHistory }: OverviewProps) {
           ) : (
             <WeekChart data={weekly} />
           )}
-          <div style={{ display: 'flex', justifyContent: 'space-between', fontSize: 10, color: 'var(--ol-ink-4)', marginTop: 8 }}>
-            {weekDayLabels(t('overview.weekDays', { returnObjects: true }) as string[]).map((d, i) => <span key={i}>{d}</span>)}
+          <div style={{ display: 'grid', gridTemplateColumns: '28px minmax(0, 1fr)', gap: 8, fontSize: 10, color: 'var(--ol-ink-4)', marginTop: 8 }}>
+            <span aria-hidden="true" />
+            <div style={{ display: 'grid', gridTemplateColumns: 'repeat(7, minmax(0, 1fr))', gap: 8 }}>
+              {weekDayLabels(t('overview.weekDays', { returnObjects: true }) as string[]).map((d, i) => <span key={i} style={{ textAlign: 'center' }}>{d}</span>)}
+            </div>
           </div>
         </Card>
 
-        <Card padding={0} style={{ display: 'flex', flexDirection: 'column', minHeight: 0, overflow: 'hidden' }}>
+        <Card padding={0} style={{ display: 'flex', flexDirection: 'column', height: mobile ? undefined : '100%', minHeight: 0, overflow: 'hidden' }}>
           <div style={{ padding: '14px 18px', borderBottom: '0.5px solid var(--ol-line)', display: 'flex', alignItems: 'center', justifyContent: 'space-between', flexShrink: 0 }}>
             <span style={{ fontSize: 12, fontWeight: 600, color: 'var(--ol-ink-2)' }}>{t('overview.recentTitle')}</span>
             <Btn size="sm" variant="ghost" onClick={onOpenHistory}>{t('overview.recentAll')}</Btn>
@@ -243,6 +260,15 @@ export function Overview({ onOpenHistory }: OverviewProps) {
           </div>
         </Card>
       </div>
+
+      {showActivityHeatmap && (
+        <ActivityHeatmapCard
+          activity={yearlyActivity}
+          mode={activityMode}
+          onModeChange={setActivityMode}
+          historyError={historyError}
+        />
+      )}
     </>
   );
 }
@@ -318,27 +344,427 @@ function Metric({ icon, label, value, trend, accent }: MetricProps) {
 
 function WeekChart({ data }: { data: number[] }) {
   const max = Math.max(...data, 1);
+  const mid = Math.ceil(max / 2);
+  return (
+    <div style={{ display: 'grid', gridTemplateColumns: '28px minmax(0, 1fr)', gap: 8, height: 108 }}>
+      <div style={{ display: 'flex', flexDirection: 'column', justifyContent: 'space-between', alignItems: 'flex-end', fontSize: 9.5, color: 'var(--ol-ink-4)', lineHeight: 1 }}>
+        <span>{max}</span>
+        <span>{mid}</span>
+        <span>0</span>
+      </div>
+      <div style={{ position: 'relative', display: 'grid', gridTemplateColumns: 'repeat(7, minmax(0, 1fr))', alignItems: 'end', gap: 8, height: 108, paddingTop: 12, borderBottom: '0.5px solid var(--ol-line)' }}>
+        <span aria-hidden="true" style={{ position: 'absolute', left: 0, right: 0, top: 12, borderTop: '0.5px solid color-mix(in srgb, var(--ol-ink) 8%, transparent)' }} />
+        <span aria-hidden="true" style={{ position: 'absolute', left: 0, right: 0, top: 58, borderTop: '0.5px solid color-mix(in srgb, var(--ol-ink) 6%, transparent)' }} />
+        {data.map((v, i) => {
+          const isToday = i === 6;
+          const barHeight = v > 0 ? Math.max(6, (v / max) * 74) : 3;
+          return (
+            <div key={i} style={{ position: 'relative', zIndex: 1, flex: 1, minWidth: 0, display: 'flex', flexDirection: 'column', alignItems: 'center', justifyContent: 'flex-end', gap: 4 }}>
+              <div style={{ fontSize: 9.5, color: isToday ? 'var(--ol-blue)' : 'var(--ol-ink-4)', fontWeight: isToday ? 700 : 500 }}>{v}</div>
+              <div
+                style={{
+                  width: '100%',
+                  height: barHeight,
+                  borderRadius: '4px 4px 1px 1px',
+                  background: isToday ? 'var(--ol-blue)' : 'color-mix(in srgb, var(--ol-blue) 58%, var(--ol-surface))',
+                  opacity: v === 0 ? 0.22 : 1,
+                  transition: 'height 0.18s var(--ol-motion-soft), opacity 0.18s var(--ol-motion-soft)',
+                }}
+              />
+            </div>
+          );
+        })}
+      </div>
+    </div>
+  );
+}
+
+interface DayActivity {
+  key: string;
+  date: Date;
+  rawCount: number;
+  rawChars: number;
+  rawDurationMs: number;
+  count: number;
+  chars: number;
+  durationMs: number;
+  level: number;
+  inRange: boolean;
+}
+
+interface WeekActivity {
+  key: string;
+  startDate: Date;
+  endDate: Date;
+  count: number;
+  chars: number;
+  durationMs: number;
+  cumulativeCount: number;
+  cumulativeChars: number;
+  cumulativeDurationMs: number;
+  value: number;
+  valueChars: number;
+  level: number;
+  inRange: boolean;
+}
+
+interface MonthLabel {
+  weekIndex: number;
+  label: string;
+}
+
+interface YearlyActivity {
+  cells: DayActivity[];
+  weeks: number;
+  weekColumns: number;
+  activeDays: number;
+  maxCount: number;
+  maxWeekValue: number;
+  weekBars: WeekActivity[];
+  monthLabels: MonthLabel[];
+  weekMonthLabels: MonthLabel[];
+}
+
+function ActivityHeatmapCard({
+  activity,
+  mode,
+  onModeChange,
+  historyError,
+}: {
+  activity: YearlyActivity;
+  mode: ActivityMode;
+  onModeChange: (mode: ActivityMode) => void;
+  historyError: boolean;
+}) {
+  const { t } = useTranslation();
+  const mobile = useMobileLayout();
+  const cardRef = useRef<HTMLDivElement | null>(null);
+  const [hoveredKey, setHoveredKey] = useState<string | null>(null);
+  const [hoverPoint, setHoverPoint] = useState<{ x: number; y: number; align: 'left' | 'center' | 'right' } | null>(null);
+  const cellSize = 12;
+  const cellGap = 4;
+  const dayGridWidth = activity.weeks * cellSize + Math.max(0, activity.weeks - 1) * cellGap;
+  const weekGridWidth = activity.weekColumns * cellSize + Math.max(0, activity.weekColumns - 1) * cellGap;
+  const hoveredDay = mode === 'daily' && hoveredKey
+    ? activity.cells.find(cell => cell.key === hoveredKey) ?? null
+    : null;
+  const hoveredWeek = mode !== 'daily' && hoveredKey
+    ? activity.weekBars.find(week => week.key === hoveredKey) ?? null
+    : null;
+  const summaryArgs = hoveredDay
+    ? activityDaySummaryArgs(hoveredDay, t)
+    : hoveredWeek && mode !== 'daily'
+      ? activityWeekSummaryArgs(mode, hoveredWeek, t)
+      : null;
+  const summaryText = summaryArgs ? t(summaryArgs.key, summaryArgs.options) : null;
+  const showTooltip = Boolean(summaryText && hoverPoint);
+  const handleHover = useCallback((key: string, event: PointerEvent<HTMLElement>) => {
+    const cardRect = cardRef.current?.getBoundingClientRect();
+    const targetRect = event.currentTarget.getBoundingClientRect();
+    if (!cardRect) return;
+    const x = targetRect.left + targetRect.width / 2 - cardRect.left;
+    const y = targetRect.top - cardRect.top;
+    const align = x < 140 ? 'left' : x > cardRect.width - 140 ? 'right' : 'center';
+    setHoveredKey(key);
+    setHoverPoint({ x, y, align });
+  }, []);
+  const clearHover = useCallback(() => {
+    setHoveredKey(null);
+    setHoverPoint(null);
+  }, []);
+
+  return (
+    <Card padding={18} style={{ marginTop: 12, overflow: 'hidden', flexShrink: 0, position: 'relative' }}>
+      <div ref={cardRef} style={{ position: 'absolute', inset: 0, pointerEvents: 'none' }} />
+      <div
+        style={{
+          display: 'grid',
+          gridTemplateColumns: mobile ? '1fr' : 'minmax(0, 1fr) auto',
+          alignItems: 'center',
+          gap: mobile ? 10 : 14,
+          marginBottom: 16,
+        }}
+      >
+        <div style={{ display: 'flex', alignItems: 'center', gap: 10, minWidth: 0, justifySelf: 'start' }}>
+          <span style={{ fontSize: 12, fontWeight: 600, color: 'var(--ol-ink-2)' }}>{t('overview.activityTitle')}</span>
+        </div>
+        <div style={{ display: 'flex', alignItems: 'center', justifyContent: mobile ? 'flex-start' : 'flex-end', gap: 4, justifySelf: mobile ? 'start' : 'end' }}>
+          {ACTIVITY_MODES.map(activityMode => {
+            const selected = activityMode === mode;
+            return (
+              <button
+                key={activityMode}
+                type="button"
+                onClick={() => onModeChange(activityMode)}
+                aria-pressed={selected}
+                style={{
+                  height: 28,
+                  padding: '0 8px',
+                  border: '0.5px solid transparent',
+                  borderRadius: 7,
+                  background: selected ? 'color-mix(in srgb, var(--ol-ink) 8%, transparent)' : 'transparent',
+                  color: selected ? 'var(--ol-ink)' : 'var(--ol-ink-4)',
+                  fontSize: 12,
+                  fontWeight: selected ? 700 : 600,
+                  cursor: 'pointer',
+                  transition: 'background 0.16s var(--ol-motion-quick), color 0.16s var(--ol-motion-quick)',
+                }}
+              >
+                {t(`overview.activityMode.${activityMode}`)}
+              </button>
+            );
+          })}
+        </div>
+      </div>
+
+      {historyError ? (
+        <div style={{ minHeight: 116, display: 'flex', alignItems: 'center', justifyContent: 'center', textAlign: 'center', fontSize: 12, color: 'var(--ol-ink-4)' }}>{t('overview.historyLoadError')}</div>
+      ) : activity.activeDays === 0 ? (
+        <div style={{ minHeight: 116, display: 'flex', alignItems: 'center', justifyContent: 'center', textAlign: 'center', fontSize: 12, color: 'var(--ol-ink-4)' }}>{t('overview.activityEmpty')}</div>
+      ) : mode === 'daily' ? (
+        <ActivityDailyGrid
+          mode={mode}
+          activity={activity}
+          cellSize={cellSize}
+          cellGap={cellGap}
+          minGridWidth={dayGridWidth}
+          hoveredKey={hoveredKey}
+          onHover={handleHover}
+          onLeave={clearHover}
+        />
+      ) : (
+        <ActivityWeekGrid
+          activity={activity}
+          mode={mode}
+          cellSize={cellSize}
+          cellGap={cellGap}
+          minGridWidth={weekGridWidth}
+          hoveredKey={hoveredKey}
+          onHover={handleHover}
+          onLeave={clearHover}
+        />
+      )}
+      {showTooltip && hoverPoint && (
+        <div
+          style={{
+            position: 'absolute',
+            left: hoverPoint.x,
+            top: Math.max(34, hoverPoint.y - 3),
+            transform: hoverPoint.align === 'left'
+              ? 'translate(0, -100%)'
+              : hoverPoint.align === 'right'
+                ? 'translate(-100%, -100%)'
+                : 'translate(-50%, -100%)',
+            zIndex: 2,
+            maxWidth: 320,
+            padding: '6px 12px',
+            border: '0.5px solid color-mix(in srgb, var(--ol-ink) 10%, transparent)',
+            borderRadius: 999,
+            background: 'var(--ol-surface)',
+            color: 'var(--ol-ink)',
+            boxShadow: '0 8px 24px color-mix(in srgb, var(--ol-ink) 12%, transparent)',
+            fontSize: 12,
+            fontWeight: 500,
+            whiteSpace: 'nowrap',
+            pointerEvents: 'none',
+          }}
+        >
+          {summaryText}
+        </div>
+      )}
+    </Card>
+  );
+}
+
+function ActivityDailyGrid({
+  mode,
+  activity,
+  cellSize,
+  cellGap,
+  minGridWidth,
+  hoveredKey,
+  onHover,
+  onLeave,
+}: {
+  mode: ActivityMode;
+  activity: YearlyActivity;
+  cellSize: number;
+  cellGap: number;
+  minGridWidth: number;
+  hoveredKey: string | null;
+  onHover: (key: string, event: PointerEvent<HTMLElement>) => void;
+  onLeave: () => void;
+}) {
+  const { t } = useTranslation();
   return (
-    <div style={{ display: 'flex', alignItems: 'flex-end', gap: 8, height: 100 }}>
-      {data.map((v, i) => {
-        const isToday = i === 6;
-        return (
-          <div key={i} style={{ flex: 1, display: 'flex', flexDirection: 'column', alignItems: 'center', gap: 4 }}>
-            <div style={{ fontSize: 9.5, color: isToday ? 'var(--ol-blue)' : 'var(--ol-ink-4)', fontWeight: isToday ? 600 : 400 }}>{v}</div>
-            <div
-              style={{
-                width: '100%',
-                height: `${(v / max) * 80}px`,
-                minHeight: 2,
-                borderRadius: 4,
-                background: isToday ? 'var(--ol-blue)' : 'var(--ol-ink-4)',
-                opacity: v === 0 ? 0.15 : isToday ? 1 : 0.85,
-                transition: 'height 0.18s var(--ol-motion-soft), opacity 0.18s var(--ol-motion-soft)',
-              }}
-            />
+    <div onPointerLeave={onLeave}>
+      <div className="ol-thinscroll" style={{ overflowX: 'auto', overflowY: 'hidden', paddingBottom: 2, flex: 1 }}>
+        <div style={{ minWidth: minGridWidth, width: 'max-content' }}>
+          <div
+            aria-label={t('overview.activityTitle')}
+            style={{
+              display: 'grid',
+              gridTemplateColumns: `repeat(${activity.weeks}, ${cellSize}px)`,
+              gridTemplateRows: `repeat(7, ${cellSize}px)`,
+              gridAutoFlow: 'column',
+              gap: cellGap,
+            }}
+          >
+            {activity.cells.map(cell => {
+              const selected = hoveredKey === cell.key;
+              const cellSummary = activityDaySummaryArgs(cell, t);
+              const weekIndex = Math.floor(differenceInDays(cell.date, activity.cells[0]?.date ?? cell.date) / 7);
+              return (
+                <div
+                  key={`${mode}-${cell.key}`}
+                  title={cell.inRange ? t(cellSummary.key, cellSummary.options) : undefined}
+                  onPointerEnter={(event) => {
+                    if (cell.inRange) onHover(cell.key, event);
+                  }}
+                  onPointerMove={(event) => {
+                    if (cell.inRange) onHover(cell.key, event);
+                  }}
+                  style={{
+                    width: cellSize,
+                    height: cellSize,
+                    borderRadius: 4,
+                    background: activityColor(cell.level),
+                    opacity: cell.inRange ? 1 : 0,
+                    boxShadow: cell.inRange
+                      ? selected
+                        ? '0 0 0 1.5px color-mix(in srgb, var(--ol-ink) 42%, transparent) inset'
+                        : '0 0 0 0.5px color-mix(in srgb, var(--ol-ink) 10%, transparent) inset'
+                      : 'none',
+                    cursor: cell.inRange ? 'default' : 'auto',
+                    transform: 'scale(1)',
+                    animation: cell.inRange ? `ol-activity-cell-in 0.22s var(--ol-motion-soft) ${Math.min(Math.max(0, weekIndex) * 5, 260)}ms both` : undefined,
+                    transition: 'background 0.16s var(--ol-motion-quick), transform 0.12s var(--ol-motion-quick), box-shadow 0.12s var(--ol-motion-quick)',
+                  }}
+                />
+              );
+            })}
           </div>
-        );
-      })}
+          <ActivityMonthLabels labels={activity.monthLabels} weeks={activity.weeks} cellSize={cellSize} cellGap={cellGap} />
+        </div>
+      </div>
+    </div>
+  );
+}
+
+function ActivityWeekGrid({
+  activity,
+  mode,
+  cellSize,
+  cellGap,
+  minGridWidth,
+  hoveredKey,
+  onHover,
+  onLeave,
+}: {
+  activity: YearlyActivity;
+  mode: Exclude<ActivityMode, 'daily'>;
+  cellSize: number;
+  cellGap: number;
+  minGridWidth: number;
+  hoveredKey: string | null;
+  onHover: (key: string, event: PointerEvent<HTMLElement>) => void;
+  onLeave: () => void;
+}) {
+  const { t } = useTranslation();
+
+  return (
+    <div onPointerLeave={onLeave}>
+      <div className="ol-thinscroll" style={{ overflowX: 'auto', overflowY: 'hidden', paddingBottom: 2, flex: 1 }}>
+      <div style={{ minWidth: minGridWidth, width: 'max-content' }}>
+        <div
+          aria-label={t(`overview.activityMode.${mode}`)}
+          style={{
+            display: 'grid',
+            gridTemplateColumns: `repeat(${activity.weekColumns}, ${cellSize}px)`,
+            gridTemplateRows: `repeat(7, ${cellSize}px)`,
+            gridAutoFlow: 'column',
+            gap: cellGap,
+          }}
+        >
+          {activity.weekBars.flatMap((week, weekIndex) => {
+            const summary = activityWeekSummaryArgs(mode, week, t);
+            const filledCells = activityDiscreteCells(week.value, activity.maxWeekValue);
+            return Array.from({ length: 7 }).map((_, rowIndex) => {
+              const selected = hoveredKey === week.key;
+              const filled = rowIndex >= 7 - filledCells;
+              return (
+              <div
+                key={`${mode}-${week.key}-${rowIndex}`}
+                title={week.inRange ? t(summary.key, summary.options) : undefined}
+                onPointerEnter={(event) => {
+                  if (week.inRange) onHover(week.key, event);
+                }}
+                onPointerMove={(event) => {
+                  if (week.inRange) onHover(week.key, event);
+                }}
+                style={{
+                  width: cellSize,
+                  height: cellSize,
+                  borderRadius: 4,
+                  background: filled ? activityColor(week.level) : activityColor(0),
+                  opacity: week.inRange ? 1 : 0,
+                  boxShadow: week.inRange
+                    ? selected
+                      ? '0 0 0 1.5px color-mix(in srgb, var(--ol-ink) 42%, transparent) inset'
+                      : '0 0 0 0.5px color-mix(in srgb, var(--ol-ink) 10%, transparent) inset'
+                    : 'none',
+                  cursor: week.inRange ? 'default' : 'auto',
+                  transform: 'scale(1)',
+                  animation: week.inRange ? `ol-activity-cell-in 0.22s var(--ol-motion-soft) ${Math.min(weekIndex * 5, 260)}ms both` : undefined,
+                  transition: 'background 0.16s var(--ol-motion-quick), transform 0.12s var(--ol-motion-quick), box-shadow 0.12s var(--ol-motion-quick)',
+                }}
+              />
+              );
+            });
+          })}
+        </div>
+        <ActivityMonthLabels labels={activity.weekMonthLabels} weeks={activity.weekColumns} cellSize={cellSize} cellGap={cellGap} />
+      </div>
+      </div>
+    </div>
+  );
+}
+
+function ActivityMonthLabels({
+  labels,
+  weeks,
+  cellSize,
+  cellGap,
+}: {
+  labels: MonthLabel[];
+  weeks: number;
+  cellSize: number;
+  cellGap: number;
+}) {
+  return (
+    <div
+      style={{
+        display: 'grid',
+        gridTemplateColumns: `repeat(${weeks}, ${cellSize}px)`,
+        columnGap: cellGap,
+        minHeight: 18,
+        marginTop: 12,
+        color: 'var(--ol-ink-4)',
+        fontSize: 11,
+      }}
+    >
+      {labels.map(label => (
+        <span
+          key={`${label.weekIndex}-${label.label}`}
+          style={{
+            gridColumn: `${label.weekIndex + 1} / span 2`,
+            whiteSpace: 'nowrap',
+            lineHeight: '16px',
+          }}
+        >
+          {label.label}
+        </span>
+      ))}
     </div>
   );
 }
@@ -363,6 +789,249 @@ function RecentRow({ session, modeLabel }: { session: DictationSession; modeLabe
   );
 }
 
+function buildYearlyActivity(history: DictationSession[], monthNames: string[], mode: ActivityMode): YearlyActivity {
+  const today = startOfLocalDay(new Date());
+  const rangeStart = addDays(today, -364);
+  const gridStart = rangeStart;
+  const weeks = Math.ceil((differenceInDays(today, gridStart) + 1) / 7);
+  const weekGridStart = startOfWeek(rangeStart);
+  const weekColumns = Math.ceil((differenceInDays(today, weekGridStart) + 1) / 7);
+  const byDay = new Map<string, { count: number; chars: number; durationMs: number }>();
+
+  history.forEach(session => {
+    const date = startOfLocalDay(new Date(session.createdAt));
+    if (isNaN(date.getTime()) || date < rangeStart || date > today) return;
+    const key = localDateKey(date);
+    const current = byDay.get(key) ?? { count: 0, chars: 0, durationMs: 0 };
+    current.count += 1;
+    current.chars += session.finalText.length;
+    current.durationMs += session.durationMs ?? 0;
+    byDay.set(key, current);
+  });
+
+  const rawCells: Array<Omit<DayActivity, 'count' | 'chars' | 'durationMs' | 'level'>> = [];
+  for (let i = 0; i < weeks * 7; i += 1) {
+    const date = addDays(gridStart, i);
+    const inRange = date >= rangeStart && date <= today;
+    const key = localDateKey(date);
+    const stats = inRange ? byDay.get(key) : undefined;
+    rawCells.push({
+      key,
+      date,
+      rawCount: stats?.count ?? 0,
+      rawChars: stats?.chars ?? 0,
+      rawDurationMs: stats?.durationMs ?? 0,
+      inRange,
+    });
+  }
+
+  let cumulativeCount = 0;
+  let cumulativeChars = 0;
+  let cumulativeDurationMs = 0;
+  const metricCells = rawCells.map(cell => ({
+    ...cell,
+    count: cell.inRange ? cell.rawCount : 0,
+    chars: cell.inRange ? cell.rawChars : 0,
+    durationMs: cell.inRange ? cell.rawDurationMs : 0,
+  }));
+
+  const maxCount = Math.max(...metricCells.filter(cell => cell.inRange).map(cell => cell.count), 0);
+  const cells = metricCells.map(cell => ({
+    ...cell,
+    level: cell.inRange ? activityLevel(cell.count, maxCount) : 0,
+  }));
+
+  const rawWeeks: Array<Omit<WeekActivity, 'level'>> = [];
+  for (let weekIndex = 0; weekIndex < weekColumns; weekIndex += 1) {
+    const startDate = addDays(weekGridStart, weekIndex * 7);
+    const endDate = addDays(startDate, 6);
+    const inRange = endDate >= rangeStart && startDate <= today;
+    let stats = { count: 0, chars: 0, durationMs: 0 };
+    for (let offset = 0; offset < 7; offset += 1) {
+      const date = addDays(startDate, offset);
+      if (date < rangeStart || date > today) continue;
+      const dayStats = byDay.get(localDateKey(date));
+      if (!dayStats) continue;
+      stats = {
+        count: stats.count + dayStats.count,
+        chars: stats.chars + dayStats.chars,
+        durationMs: stats.durationMs + dayStats.durationMs,
+      };
+    }
+    if (inRange) {
+      cumulativeCount += stats.count;
+      cumulativeChars += stats.chars;
+      cumulativeDurationMs += stats.durationMs;
+    }
+    const value = mode === 'cumulative' ? cumulativeCount : stats.count;
+    const valueChars = mode === 'cumulative' ? cumulativeChars : stats.chars;
+    rawWeeks.push({
+      key: localDateKey(startDate),
+      startDate,
+      endDate: endDate > today ? today : endDate,
+      count: inRange ? stats.count : 0,
+      chars: inRange ? stats.chars : 0,
+      durationMs: inRange ? stats.durationMs : 0,
+      cumulativeCount: inRange ? cumulativeCount : 0,
+      cumulativeChars: inRange ? cumulativeChars : 0,
+      cumulativeDurationMs: inRange ? cumulativeDurationMs : 0,
+      value: inRange ? value : 0,
+      valueChars: inRange ? valueChars : 0,
+      inRange,
+    });
+  }
+
+  const maxWeekValue = Math.max(...rawWeeks.filter(week => week.inRange).map(week => week.value), 0);
+  const weekBars = rawWeeks.map(week => ({
+    ...week,
+    level: week.inRange ? activityLevel(week.value, maxWeekValue) : 0,
+  }));
+
+  const monthLabels: MonthLabel[] = [];
+  let lastMonth = -1;
+  for (let weekIndex = 0; weekIndex < weeks; weekIndex += 1) {
+    const weekCells = cells.slice(weekIndex * 7, weekIndex * 7 + 7).filter(cell => cell.inRange);
+    const candidate = weekCells.find(cell => cell.date.getDate() === 1);
+    if (!candidate) continue;
+    const month = candidate.date.getMonth();
+    if (month === lastMonth) continue;
+    lastMonth = month;
+    monthLabels.push({
+      weekIndex,
+      label: monthNames[month] ?? String(month + 1),
+    });
+  }
+  const weekMonthLabels: MonthLabel[] = [];
+  let lastWeekMonth = -1;
+  for (let weekIndex = 0; weekIndex < weekColumns; weekIndex += 1) {
+    let candidate: Date | null = null;
+    const weekStart = addDays(weekGridStart, weekIndex * 7);
+    for (let offset = 0; offset < 7; offset += 1) {
+      const date = addDays(weekStart, offset);
+      if (date >= rangeStart && date <= today && date.getDate() === 1) {
+        candidate = date;
+        break;
+      }
+    }
+    if (!candidate) continue;
+    const month = candidate.getMonth();
+    if (month === lastWeekMonth) continue;
+    lastWeekMonth = month;
+    weekMonthLabels.push({
+      weekIndex,
+      label: monthNames[month] ?? String(month + 1),
+    });
+  }
+
+  return {
+    cells,
+    weeks,
+    weekColumns,
+    activeDays: rawCells.filter(cell => cell.inRange && cell.rawCount > 0).length,
+    maxCount,
+    maxWeekValue,
+    weekBars,
+    monthLabels,
+    weekMonthLabels,
+  };
+}
+
+function activityLevel(count: number, maxCount: number): number {
+  if (count <= 0 || maxCount <= 0) return 0;
+  const ratio = count / maxCount;
+  if (ratio <= 0.25) return 1;
+  if (ratio <= 0.5) return 2;
+  if (ratio <= 0.75) return 3;
+  return 4;
+}
+
+function activityDiscreteCells(value: number, maxValue: number): number {
+  if (value <= 0 || maxValue <= 0) return 0;
+  return Math.min(7, Math.max(1, Math.ceil((value / maxValue) * 7)));
+}
+
+function activityColor(level: number): string {
+  const base = 'var(--ol-blue)';
+  switch (level) {
+    case 1:
+      return `color-mix(in srgb, ${base} 26%, var(--ol-surface))`;
+    case 2:
+      return `color-mix(in srgb, ${base} 44%, var(--ol-surface))`;
+    case 3:
+      return `color-mix(in srgb, ${base} 68%, var(--ol-surface))`;
+    case 4:
+      return base;
+    default:
+      return 'color-mix(in srgb, var(--ol-ink) 8%, var(--ol-surface))';
+  }
+}
+
+function activityDaySummaryArgs(cell: DayActivity, t: ReturnType<typeof useTranslation>['t']): { key: string; options: Record<string, string | number> } {
+  const date = formatHeatmapMonthDay(cell.date);
+  return {
+    key: 'overview.activitySummaryDaily',
+    options: {
+      date,
+      count: cell.rawCount.toLocaleString(),
+      chars: cell.rawChars.toLocaleString(),
+      duration: formatDuration(cell.rawDurationMs, t),
+    },
+  };
+}
+
+function activityWeekSummaryArgs(mode: Exclude<ActivityMode, 'daily'>, week: WeekActivity, t: ReturnType<typeof useTranslation>['t']): { key: string; options: Record<string, string | number> } {
+  const start = formatHeatmapDisplayDate(week.startDate);
+  if (mode === 'weekly') {
+    return {
+      key: 'overview.activitySummaryWeekly',
+      options: {
+        start,
+        count: week.count.toLocaleString(),
+        chars: week.chars.toLocaleString(),
+        duration: formatDuration(week.durationMs, t),
+      },
+    };
+  }
+  return {
+    key: 'overview.activitySummaryCumulative',
+    options: {
+      start,
+      count: week.cumulativeCount.toLocaleString(),
+      chars: week.cumulativeChars.toLocaleString(),
+      duration: formatDuration(week.cumulativeDurationMs, t),
+    },
+  };
+}
+
+function startOfLocalDay(date: Date): Date {
+  return new Date(date.getFullYear(), date.getMonth(), date.getDate());
+}
+
+function startOfWeek(date: Date): Date {
+  return addDays(startOfLocalDay(date), -((date.getDay() + 6) % 7));
+}
+
+function addDays(date: Date, days: number): Date {
+  return new Date(date.getFullYear(), date.getMonth(), date.getDate() + days);
+}
+
+function differenceInDays(a: Date, b: Date): number {
+  return Math.round((startOfLocalDay(a).getTime() - startOfLocalDay(b).getTime()) / 86400000);
+}
+
+function localDateKey(date: Date): string {
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())}`;
+}
+
+function formatHeatmapDisplayDate(date: Date): string {
+  return date.toLocaleDateString(undefined, { year: 'numeric', month: 'long', day: 'numeric' });
+}
+
+function formatHeatmapMonthDay(date: Date): string {
+  return date.toLocaleDateString(undefined, { month: 'long', day: 'numeric' });
+}
+
 function formatTime(iso: string): string {
   const d = new Date(iso);
   if (isNaN(d.getTime())) return iso;
@@ -374,10 +1043,11 @@ function formatTime(iso: string): string {
 }
 
 function formatDuration(ms: number, t: ReturnType<typeof useTranslation>['t']): string {
-  if (ms <= 0) return '—';
+  if (ms <= 0) return t('common.durationSeconds', { value: '0' });
   const sec = ms / 1000;
   if (sec < 60) return t('common.durationSeconds', { value: sec.toFixed(1) });
-  return `${Math.floor(sec / 60)}:${String(Math.floor(sec % 60)).padStart(2, '0')}`;
+  if (sec < 3600) return t('common.durationMinutes', { value: (sec / 60).toFixed(1) });
+  return t('common.durationHours', { value: (sec / 3600).toFixed(1) });
 }
 
 function weekDayLabels(names: string[]): string[] {
diff --git a/openless-all/app/src/pages/settings/DataStorageSection.tsx b/openless-all/app/src/pages/settings/DataStorageSection.tsx
index 5727a747..c2dcc217 100644
--- a/openless-all/app/src/pages/settings/DataStorageSection.tsx
+++ b/openless-all/app/src/pages/settings/DataStorageSection.tsx
@@ -6,7 +6,7 @@ import { useHotkeySettings } from '../../state/HotkeySettingsContext';
 import { Card } from '../_atoms';
 import { SettingRow, SectionTitle, inputStyle } from './shared';
 
-// 范围限制：retention 0-365 天，context window 0-60 分钟（再大对实际对话场景没意义且白烧 token）。
+// 范围限制：context window 0-60 分钟（再大对实际对话场景没意义且白烧 token）。
 const clamp = (n: number, min: number, max: number) => Math.max(min, Math.min(max, n));
 
 export function DataStorageSection() {
@@ -21,28 +21,27 @@ export function DataStorageSection() {
     );
   }
 
-  // 空字符串时回滚到默认值。
+  // 空字符串 / 0 = 不限；输入框用文字占位，不把 0 展示成一个普通天数。
   const onHistoryRetentionChange = (raw: string) => {
     const parsed = raw === '' ? 0 : Number.parseInt(raw, 10);
     if (Number.isNaN(parsed)) return;
-    void savePrefs({ ...prefs, historyRetentionDays: clamp(parsed, 0, 365) });
+    void savePrefs({ ...prefs, historyRetentionDays: Math.max(0, parsed) });
   };
   const onPolishContextWindowChange = (raw: string) => {
     const parsed = raw === '' ? 0 : Number.parseInt(raw, 10);
     if (Number.isNaN(parsed)) return;
     void savePrefs({ ...prefs, polishContextWindowMinutes: clamp(parsed, 0, 60) });
   };
-  // 历史条数 200 是当前 HISTORY_CAP（persistence.rs:32），下限 5 是避免用户填 0 导致
-  // 写一条就立刻被清光；空字符串视为不限制，落回 null → 后端走 200 默认。
+  // 空字符串 / 0 = 不限。
   const onHistoryMaxEntriesChange = (raw: string) => {
     const trimmed = raw.trim();
-    if (trimmed === '') {
+    if (trimmed === '' || trimmed === '0') {
       void savePrefs({ ...prefs, historyMaxEntries: null });
       return;
     }
     const parsed = Number.parseInt(trimmed, 10);
     if (Number.isNaN(parsed)) return;
-    void savePrefs({ ...prefs, historyMaxEntries: clamp(parsed, 5, 200) });
+    void savePrefs({ ...prefs, historyMaxEntries: Math.max(1, parsed) });
   };
 
   return (
@@ -52,8 +51,8 @@ export function DataStorageSection() {
         <input
           type="number"
           min={0}
-          max={365}
-          value={prefs.historyRetentionDays}
+          placeholder={t('common.unlimited')}
+          value={prefs.historyRetentionDays === 0 ? '' : prefs.historyRetentionDays}
           onChange={e => onHistoryRetentionChange(e.target.value)}
           style={{ ...inputStyle, width: 80, textAlign: 'right' }}
         />
@@ -61,9 +60,8 @@ export function DataStorageSection() {
       <SettingRow label={t('settings.recording.historyMaxEntriesLabel')}>
         <input
           type="number"
-          min={5}
-          max={200}
-          placeholder="200"
+          min={1}
+          placeholder={t('common.unlimited')}
           value={prefs.historyMaxEntries ?? ''}
           onChange={e => onHistoryMaxEntriesChange(e.target.value)}
           style={{ ...inputStyle, width: 80, textAlign: 'right' }}
diff --git a/openless-all/app/src/pages/settings/ThemeSection.tsx b/openless-all/app/src/pages/settings/ThemeSection.tsx
index f27075a0..2fd9a6ea 100644
--- a/openless-all/app/src/pages/settings/ThemeSection.tsx
+++ b/openless-all/app/src/pages/settings/ThemeSection.tsx
@@ -3,7 +3,7 @@ import { useTranslation } from 'react-i18next';
 import { useHotkeySettings } from '../../state/HotkeySettingsContext';
 import { SelectLite } from '../../components/ui/SelectLite';
 import { Card } from '../_atoms';
-import { SettingRow } from './shared';
+import { SettingRow, Toggle } from './shared';
 import {
   readThemePreference,
   setThemePreference,
@@ -53,6 +53,19 @@ export function ThemeSection() {
           style={{ maxWidth: 220, minWidth: 200 }}
         />
       </SettingRow>
+      {prefs && (
+        <SettingRow label={t('settings.theme.overviewActivityLabel')}>
+          <div style={{ display: 'flex', alignItems: 'center', gap: 10, minWidth: 0 }}>
+            <Toggle
+              on={prefs.showOverviewActivityHeatmap !== false}
+              onToggle={next => void updatePrefs({ ...prefs, showOverviewActivityHeatmap: next })}
+            />
+            <span style={{ fontSize: 11.5, color: 'var(--ol-ink-4)', lineHeight: 1.45 }}>
+              {t('settings.theme.overviewActivityDesc')}
+            </span>
+          </div>
+        </SettingRow>
+      )}
     </Card>
   );
 }
diff --git a/openless-all/app/src/styles/global.css b/openless-all/app/src/styles/global.css
index dc08e742..319f0814 100644
--- a/openless-all/app/src/styles/global.css
+++ b/openless-all/app/src/styles/global.css
@@ -122,6 +122,11 @@ a { color: inherit; text-decoration: none; }
   to { transform: rotate(360deg); }
 }
 
+@keyframes ol-activity-cell-in {
+  from { opacity: 0; }
+  to   { opacity: 1; }
+}
+
 @keyframes ol-modal-drawer-in {
   from {
     opacity: 0;