refactor: improve mobile layout, sticky footer, and UI spacing

src/components/Footer.vue

@@ -4,7 +4,7 @@ const version = __APP_VERSION__;
 </script>
 
 <template>
-  <footer class="app-footer unselectable">
+  <footer class="app-footer glass-panel unselectable">
     <div class="footer-content">
       <p>&copy; {{ currentYear }} Tools App. v{{ version }}</p>
     </div>
@@ -14,13 +14,18 @@ const version = __APP_VERSION__;
 <style scoped>
 .app-footer {
   width: 100%;
-  padding: 1rem;
-  background-color: #242424;
-  border-top: 1px solid rgba(255, 255, 255, 0.1);
+  padding: 0.5rem;
+  /* Background handled by glass-panel */
+  border-left: none;
+  border-right: none;
+  border-bottom: none;
+  border-radius: 0;
   display: flex;
   align-items: center;
   justify-content: center;
   margin-top: auto; /* Push to bottom in flex container */
+  z-index: 10;
+  height: 30px;
 }
 
 .footer-content {
@@ -31,7 +36,7 @@ const version = __APP_VERSION__;
 
 p {
   font-size: 0.9rem;
-  color: rgba(255, 255, 255, 0.6);
+  color: var(--text-muted);
   margin: 0;
   font-family: monospace;
 }