Enlarge header subtitle with underline and dash prefix.

Co-authored-by: Cursor <cursoragent@cursor.com>

control/frontend/src/App.tsx

@@ -28,7 +28,7 @@ function Shell({ children }: { children: ReactNode }) {
         <div className="header-top">
           <div className="header-title-wrap">
             <div className="header-title">自动化对冲监控系统</div>
-            <div className="header-subtitle">比特骆驼开发定制</div>
+            <div className="header-subtitle">—— 比特骆驼开发定制</div>
           </div>
         </div>
         <div className="header-bar">

control/frontend/src/styles.css

@@ -85,13 +85,18 @@ body {
 
 .header-subtitle {
   align-self: flex-end;
-  margin-top: 4px;
+  margin-top: 6px;
   margin-right: -0.4em;
-  padding-left: 2.5em;
-  font-size: 0.78rem;
-  letter-spacing: 0.2em;
+  padding-left: 1.2em;
+  padding-bottom: 2px;
+  font-size: 0.95rem;
+  letter-spacing: 0.16em;
   color: var(--muted);
   white-space: nowrap;
+  text-decoration: underline;
+  text-underline-offset: 4px;
+  text-decoration-thickness: 1px;
+  text-decoration-color: rgba(0, 200, 255, 0.45);
 }
 
 .header-bar {