n

frontend/src/pages/activity/Detail.jsx

@@ -24,6 +24,7 @@ const ActivityDetail = () => {
   const headerBg = useTransform(scrollY, [0, 60], ['rgba(255,255,255,0)', 'rgba(255,255,255,1)']);
   const headerShadow = useTransform(scrollY, [0, 60], ['none', '0 2px 8px rgba(0,0,0,0.1)']);
   const headerColor = useTransform(scrollY, [0, 60], ['rgba(255,255,255,1)', 'rgba(0,0,0,0.85)']);
+  const titleOpacity = useTransform(scrollY, [100, 200], [0, 1]);
 
   const { data: activity, isLoading, error } = useQuery({
     queryKey: ['activity', id],
@@ -140,7 +141,7 @@ const ActivityDetail = () => {
           <ArrowLeftOutlined />
         </motion.div>
         <motion.div 
-          style={{ color: headerColor, fontWeight: 600, opacity: useTransform(scrollY, [100, 200], [0, 1]) }}
+          style={{ color: headerColor, fontWeight: 600, opacity: titleOpacity }}
         >
           {activity.title}
         </motion.div>
@@ -222,6 +223,15 @@ const ActivityDetail = () => {
           {signUpMutation.isPending ? '提交中...' : activity.is_signed_up ? '已报名' : '立即报名'}
         </motion.button>
       </div>
+
+      <LoginModal 
+        visible={loginVisible} 
+        onClose={() => setLoginVisible(false)}
+        onLoginSuccess={(userData) => {
+          login(userData);
+          // Auto trigger signup after login if needed, or just let user click again
+        }}
+      />
     </motion.div>
   );
 };