네비게이션 바 디자인 전환 기능 추가

src/main/resources/static/css/main.css

@@ -628,6 +628,87 @@ hr {
   --shadow-xl: 0 16px 40px rgba(75, 155, 255, 0.2);
 }
 
+.design-survey-bar {
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  height: 48px;
+  background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
+  z-index: 400;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
+}
+.design-survey-bar .survey-container {
+  display: flex;
+  align-items: center;
+  gap: 16px;
+}
+.design-survey-bar .survey-label {
+  color: #ffffff;
+  font-size: 14px;
+  font-weight: 500;
+}
+.design-survey-bar .survey-buttons {
+  display: flex;
+  gap: 8px;
+}
+.design-survey-bar .survey-btn {
+  padding: 6px 16px;
+  border: 2px solid rgba(255, 255, 255, 0.5);
+  border-radius: 20px;
+  background: transparent;
+  color: #ffffff;
+  font-size: 14px;
+  font-weight: 600;
+  cursor: pointer;
+  transition: all 0.3s ease;
+}
+.design-survey-bar .survey-btn:hover {
+  background: rgba(255, 255, 255, 0.2);
+  border-color: #ffffff;
+}
+.design-survey-bar .survey-btn.active {
+  background: #ffffff;
+  color: #667eea;
+  border-color: #ffffff;
+}
+@media (max-width: 768px) {
+  .design-survey-bar {
+    height: 40px;
+  }
+  .design-survey-bar .survey-label {
+    display: none;
+  }
+  .design-survey-bar .survey-btn {
+    padding: 4px 12px;
+    font-size: 12px;
+  }
+}
+
+body.design-survey-active .global-header {
+  margin-top: 48px;
+}
+@media (max-width: 768px) {
+  body.design-survey-active .global-header {
+    margin-top: 40px;
+  }
+}
+
+body.design-variant-B .logo-text {
+  font-size: 18px !important;
+}
+body.design-variant-B .nav-link {
+  margin: 0 20px !important;
+}
+
+body.design-variant-C .nav-link {
+  margin: 0 20px !important;
+  font-weight: bold !important;
+}
+
 .blind {
   position: absolute;
   width: 1px;