style(web-app): TopNavBar 品牌名采用登录页标题字体样式

web-app/src/components/TopNavBar.vue

@@ -131,8 +131,11 @@ const roleText = ''
 }
 
 .brand-name {
-  font-size: 15px;
-  letter-spacing: 0.5px;
+  font-family: "Songti SC", "Noto Serif SC", serif;
+  font-size: clamp(18px, 2vw, 22px);
+  font-weight: 700;
+  letter-spacing: 6px;
+  color: #1A2438;
 }
 
 .nav-main {