diff --git a/app/static/app.js b/app/static/app.js
index ba605d0..f5dcd99 100644
--- a/app/static/app.js
+++ b/app/static/app.js
@@ -234,7 +234,7 @@
         ${hist.length > 0
           ? `<div class="spark-wrap">
               <div class="spark-title">余额历史 · ${WINDOW_LABELS[win]}（${hist.length} 条${th !== null ? `，虚线阈值 ${th}` : ""}）</div>
-              <canvas class="card-chart" data-aid="${a.id}"></canvas>
+              <div class="chart-box"><canvas class="card-chart" data-aid="${a.id}"></canvas></div>
               <div class="window-switch" data-aid="${a.id}">${winBtns}</div>
             </div>`
           : ""}
diff --git a/app/static/style.css b/app/static/style.css
index e8c4d8d..c76d2f3 100644
--- a/app/static/style.css
+++ b/app/static/style.css
@@ -597,12 +597,19 @@ label { font-size: 12px; font-weight: 500; color: var(--text-2); margin-bottom:
   width: 100%;
   height: 30px;
 }
-/* 卡片迷你图（Chart.js canvas） */
-.card-chart {
-  display: block;
-  width: 100%;
+/* 卡片迷你图（Chart.js canvas）——chart-box 固定高度，canvas 绝对定位，
+   避免 Chart.js responsive 尺寸与容器高度互相反馈导致无限变高 */
+.chart-box {
+  position: relative;
   height: 36px;
 }
+.card-chart {
+  position: absolute;
+  inset: 0;
+  width: 100% !important;
+  height: 100% !important;
+  display: block;
+}
 .spark-title {
   font-size: 10px;
   color: var(--text-3);