diff --git a/static/app.js b/static/app.js
index 96f619e..0bb445f 100644
--- a/static/app.js
+++ b/static/app.js
@@ -12,6 +12,7 @@
   var autoSaveTimer = null;  // 自动保存防抖
   var lastSavedData = null;  // 上次保存快照
   var lastSavedDate = null;  // 上次保存日期
+  var selectedDate = null;   // 日历中选中日期
 
   /* 勤学预设项目 */
   var PRESET_STUDY_ITEMS = [
@@ -163,6 +164,7 @@
       var isOtherMonth = false;
 
       if (isSameDay(cur, today)) classes.push('today');
+      if (ds === selectedDate) classes.push('selected');
       var status = calendarStatus[ds];
       if (status) classes.push(status);
 
@@ -189,9 +191,11 @@
 
   /** 导航到指定日期 */
   function navigateToDate(date) {
+    selectedDate = date;
     switchPanel('daily');
     document.getElementById('check-date').value = date;
     loadCheckin();
+    renderCalendar(); // 刷新日历高亮
   }
 
   /** 回到今天 */
@@ -643,6 +647,7 @@
     var todayStr = fmtDate(today);
     if (cd) cd.value = todayStr;
 
+    selectedDate = todayStr;
     initStudyPresets();
     bindAutoSave();
     lastSavedDate = todayStr;
diff --git a/static/style.css b/static/style.css
index 2a23ac0..09902c1 100644
--- a/static/style.css
+++ b/static/style.css
@@ -252,6 +252,20 @@ body {
   background: var(--primary-light);
 }
 
+.cal-cell.selected {
+  font-weight: 600;
+  color: var(--primary-dark);
+  border-color: var(--primary-dark);
+  background: #DDE3FD;
+}
+
+.cal-cell.selected.today {
+  font-weight: 700;
+  color: #FFF;
+  border-color: var(--primary-dark);
+  background: var(--primary);
+}
+
 .cal-cell::after {
   content: '';
   position: absolute;