diff --git a/config.py b/config.py
index 2482292..fe42366 100644
--- a/config.py
+++ b/config.py
@@ -414,7 +414,7 @@ YOUTUBE_API_KEY = os.getenv('YOUTUBE_API_KEY', '')
 # ==========================================
 # 系統版本與路徑
 # ==========================================
-SYSTEM_VERSION = "V10.803"
+SYSTEM_VERSION = "V10.804"
 LOG_FILE_PATH = os.path.join(BASE_DIR, 'logs/system.log')
 public_url = PUBLIC_URL  # 用於模板顯示
 
diff --git a/templates/monthly_summary_analysis.html b/templates/monthly_summary_analysis.html
index b4823f4..cd49834 100644
--- a/templates/monthly_summary_analysis.html
+++ b/templates/monthly_summary_analysis.html
@@ -153,6 +153,14 @@
       </div>
     </section>
 
+    <section class="ms-period-empty" id="monthlyPeriodEmptyState" role="status" hidden>
+      <i class="fas fa-calendar-xmark" aria-hidden="true"></i>
+      <div>
+        <strong><span id="monthlyPeriodEmptyLabel">所選期間</span>尚無本期月結明細</strong>
+        <p>頁面不會混入其他月份；仍保留去年同期資料供趨勢比較。</p>
+      </div>
+    </section>
+
     <section class="row g-3 mb-4 ms-highlight-grid" id="highlightsRow" style="display: none;" aria-label="Top 3 品牌洞察">
       <div class="col-md-4">
         <article class="card h-100 border-0 shadow-sm overflow-hidden ms-highlight ms-highlight--accent">
diff --git a/templates/sales_analysis.html b/templates/sales_analysis.html
index 52d6ccb..395af2e 100644
--- a/templates/sales_analysis.html
+++ b/templates/sales_analysis.html
@@ -63,7 +63,7 @@
         {% if db_data_range %}
         <span class="sa-tag sa-tag--neutral">
           <i class="fas fa-calendar-alt" aria-hidden="true"></i>
-          資料期間：{{ db_data_range }}
+          資料庫涵蓋：{{ db_data_range }}
         </span>
         {% endif %}
       </div>
diff --git a/tests/test_analysis_period_linkage.py b/tests/test_analysis_period_linkage.py
index 8e916fa..ee98a56 100644
--- a/tests/test_analysis_period_linkage.py
+++ b/tests/test_analysis_period_linkage.py
@@ -278,3 +278,5 @@ def test_monthly_frontend_has_replayable_period_and_no_fixed_years():
     assert "2024" not in route
     assert "2025" not in route
     assert "data-analysis-target" in tabs
+    assert "renderChartEmpty" in script
+    assert "未以其他月份回填" in script
diff --git a/web/static/css/page-monthly-summary-bem.css b/web/static/css/page-monthly-summary-bem.css
index 578630c..0eae8c4 100644
--- a/web/static/css/page-monthly-summary-bem.css
+++ b/web/static/css/page-monthly-summary-bem.css
@@ -156,6 +156,33 @@
   border: 1px solid var(--momo-border-subtle);
   border-radius: 4px;
 }
+.ms-period-empty {
+  display: flex;
+  align-items: flex-start;
+  gap: 12px;
+  margin-bottom: 16px;
+  border-left: 4px solid var(--momo-page-accent);
+  padding: 14px 16px;
+  background: var(--momo-surface-muted, rgba(248, 250, 252, 0.88));
+}
+.ms-period-empty[hidden] {
+  display: none;
+}
+.ms-period-empty i {
+  margin-top: 2px;
+  color: var(--momo-page-accent);
+  font-size: 1.15rem;
+}
+.ms-period-empty strong {
+  color: var(--momo-text-primary);
+  font-size: var(--momo-text-body, 14px);
+}
+.ms-period-empty p {
+  margin: 4px 0 0;
+  color: var(--momo-text-secondary);
+  font-size: var(--momo-text-body-sm, 13px);
+  line-height: 1.5;
+}
 .ms-filter-group__label {
   display: flex; align-items: center; gap: 6px;
   font-family: var(--momo-font-display);
diff --git a/web/static/js/page-monthly-summary.js b/web/static/js/page-monthly-summary.js
index a1b369e..e99e4c9 100644
--- a/web/static/js/page-monthly-summary.js
+++ b/web/static/js/page-monthly-summary.js
@@ -219,6 +219,13 @@
   function updateUI(data) {
     const period = data.period || {};
     $('#activeReportPeriod').text(period.label || '全部資料');
+    const periodEmpty = Number(data.total_rows || 0) === 0;
+    const periodEmptyState = document.getElementById('monthlyPeriodEmptyState');
+    if (periodEmptyState) {
+      periodEmptyState.hidden = !periodEmpty;
+      const periodEmptyLabel = document.getElementById('monthlyPeriodEmptyLabel');
+      if (periodEmptyLabel) periodEmptyLabel.textContent = period.label || '所選期間';
+    }
     if (!currentFilters.year && !currentFilters.month && !currentFilters.start_month && period.start_month) {
       currentFilters.start_month = period.start_month;
       currentFilters.end_month = period.end_month;
@@ -273,6 +280,25 @@
     renderAreaRankingChart(areaRankingChart, 'areaRankingChartTableBody', data.area_ranking, period);
   }
 
+  function renderChartEmpty(chart, tableBodyId, message) {
+    if (!chart) return;
+    chart.clear();
+    chart.setOption({
+      title: {
+        text: '尚無可繪製資料',
+        subtext: message,
+        left: 'center',
+        top: 'middle',
+        textStyle: { color: '#3f3a34', fontSize: 15, fontWeight: 700 },
+        subtextStyle: { color: '#746b61', fontSize: 12, lineHeight: 18 }
+      },
+      series: []
+    });
+    if (tableBodyId) {
+      $(`#${tableBodyId}`).html(`<tr><td class="text-muted py-3">${message}</td></tr>`);
+    }
+  }
+
   // ── Highlights (Top 3) ────────────────────────────────
   function updateHighlights(h) {
     if (!h || (!h.rev_top.length && !h.profit_top.length)) { $('#highlightsRow').hide(); return; }
@@ -288,7 +314,11 @@
 
   // ── Excel-style 主對比圖 ─────────────────────────────
   function renderExcelChart(chart, tableBodyId, trend, period = {}) {
-    if (!trend) return;
+    if (!trend || !trend.length) {
+      renderChartEmpty(chart, tableBodyId, '所選期間與去年同期皆無月結資料。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const years = [...new Set(trend.map(t => t.date.split('/')[0]))].sort().reverse();
     const currYear = String(period.current_year || years[0] || new Date().getFullYear());
@@ -362,7 +392,11 @@
 
   // ── YoY Trend ─────────────────────────────────────────
   function renderYoYTrendChart(chart, tableId, data) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, tableId, '所選期間尚無本期業績，未以其他月份回填。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const dates = data.map(d => d.date.split('/')[1] + '月');
     const currData = data.map(d => d.curr);
@@ -391,7 +425,11 @@
 
   // ── 類別分佈 (雙圓餅) ─────────────────────────────────
   function renderDivisionDistChart(chart, _tableId, data, period = {}) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, _tableId, '所選期間與去年同期皆無類別業績。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const previousLabel = period.previous_label || `${period.previous_year || ''} 年`;
     const currentLabel = period.label || `${period.current_year || ''} 年`;
@@ -414,7 +452,11 @@
 
   // ── 價格帶 ────────────────────────────────────────────
   function renderPriceRangeChart(chart, tableId, data, period = {}) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, tableId, '所選期間與去年同期皆無價格帶資料。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const order = ['0-499','500-999','1,000-1,999','2,000-4,999','5,000-9,999','10,000+'];
     data.sort((a,b) => order.indexOf(a.range) - order.indexOf(b.range));
@@ -458,7 +500,11 @@
 
   // ── BCG 矩陣（4 象限顯式配色） ───────────────────────
   function renderBCGMatrixChart(chart, data) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, null, '所選期間尚無可建立品牌策略矩陣的本期資料。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const C_STAR     = 'var(--momo-warm-olive, #6f7a4a)';
     const C_COW      = 'var(--momo-warm-honey, #c89043)';
@@ -492,7 +538,11 @@
 
   // ── 散佈圖（價/量） ──────────────────────────────────
   function renderScatterChart(chart, data) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, null, '所選期間尚無可比較價格與銷量的本期資料。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const series = data.map(d => {
       const avg = d.qty > 0 ? Math.round(d.sales / d.qty) : 0;
@@ -509,7 +559,11 @@
 
   // ── 廠商排行 ──────────────────────────────────────────
   function renderVendorRankingChart(chart, tableId, data, period = {}) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, tableId, '所選期間與去年同期皆無廠商業績。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const cd = data.slice().reverse();
     const previousLabel = period.previous_label || '去年同期';
@@ -560,7 +614,11 @@
 
   // ── 季節熱力圖 ────────────────────────────────────────
   function renderSeasonalityHeatmap(chart, data, _period = {}) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, null, '所選期間與去年同期皆無季節分佈資料。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const months = ['1月','2月','3月','4月','5月','6月','7月','8月','9月','10月','11月','12月'];
     const areaSales = {};
@@ -591,7 +649,11 @@
 
   // ── 區域排行 ──────────────────────────────────────────
   function renderAreaRankingChart(chart, tableId, data, period = {}) {
-    if (!data || !data.length) return;
+    if (!data || !data.length) {
+      renderChartEmpty(chart, tableId, '所選期間與去年同期皆無區域業績。');
+      return;
+    }
+    chart.clear();
     const compact = isCompactViewport();
     const previousLabel = period.previous_label || '去年同期';
     const currentLabel = period.label || '本期';