diff --git a/main.js b/main.js
index 820c023..2870187 100644
--- a/main.js
+++ b/main.js
@@ -14755,24 +14755,62 @@
     function getCustomMonthRange(monthsAgo) {
         const now = new Date();
         let year = now.getFullYear();
-        let month = now.getMonth() - monthsAgo;
-        while (month < 0) {
-            month += 12;
-            year--;
+        let month = now.getMonth();
+        let day = now.getDate();
+
+        // 如果今天是21号及以后，当前周期是本月21到下月20
+        // 否则，周期是上月21到本月20
+        if (day >= 21) {
+            month = month - monthsAgo;
+            let startYear = year, startMonth = month;
+            while (startMonth < 0) {
+                startMonth += 12;
+                startYear--;
+            }
+            let endYear = startYear, endMonth = startMonth + 1;
+            if (endMonth > 11) {
+                endMonth -= 12;
+                endYear++;
+            }
+            const firstDay = new Date(startYear, startMonth, 21);
+            const lastDay = new Date(endYear, endMonth, 20);
+            const formatLocal = (date) => {
+                return date.toLocaleDateString('en-CA', { 
+                    year: 'numeric', 
+                    month: '2-digit', 
+                    day: '2-digit' 
+                }).replace(/\//g, '-');
+            };
+            return {
+                firstDay: formatLocal(firstDay),
+                lastDay: formatLocal(lastDay)
+            };
+        } else {
+            month = month - monthsAgo - 1;
+            let startYear = year, startMonth = month;
+            while (startMonth < 0) {
+                startMonth += 12;
+                startYear--;
+            }
+            let endYear = startYear, endMonth = startMonth + 1;
+            if (endMonth > 11) {
+                endMonth -= 12;
+                endYear++;
+            }
+            const firstDay = new Date(startYear, startMonth, 21);
+            const lastDay = new Date(endYear, endMonth, 20);
+            const formatLocal = (date) => {
+                return date.toLocaleDateString('en-CA', { 
+                    year: 'numeric', 
+                    month: '2-digit', 
+                    day: '2-digit' 
+                }).replace(/\//g, '-');
+            };
+            return {
+                firstDay: formatLocal(firstDay),
+                lastDay: formatLocal(lastDay)
+            };
         }
-        const firstDay = new Date(year, month - 1, 21);
-        const lastDay = new Date(year, month, 20);
-        const formatLocal = (date) => {
-            return date.toLocaleDateString('en-CA', { 
-                year: 'numeric', 
-                month: '2-digit', 
-                day: '2-digit' 
-            }).replace(/\//g, '-');
-        };
-        return {
-            firstDay: formatLocal(firstDay),
-            lastDay: formatLocal(lastDay)
-        };
     }
 
     // 创建菜单按钮