diff --git a/frontend/src/App.css b/frontend/src/App.css
index d1645dd..ca9e217 100644
--- a/frontend/src/App.css
+++ b/frontend/src/App.css
@@ -1392,6 +1392,11 @@ body {
   to { opacity: 1; }
 }
 
+@keyframes slideUp {
+  from { opacity: 0; transform: translateY(20px); }
+  to { opacity: 1; transform: translateY(0); }
+}
+
 /* ---- Scrollbar ---- */
 
 ::-webkit-scrollbar {
@@ -2206,7 +2211,7 @@ body {
 }
 
 /* ============================================================
-   Custom Scenarios Styles
+   Custom Scenarios Styles — 白色商务风格（使用 CSS 变量）
    ============================================================ */
 
 /* Scenario list */
@@ -2222,16 +2227,16 @@ body {
   align-items: center;
   gap: 10px;
   padding: 10px 12px;
-  background: rgba(255, 255, 255, 0.03);
-  border: 1px solid rgba(255, 255, 255, 0.08);
-  border-radius: 8px;
+  background: var(--color-surface-2);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
   cursor: pointer;
-  transition: all 0.2s;
+  transition: all var(--transition-fast);
 }
 
 .scenario-item:hover {
-  background: rgba(255, 255, 255, 0.06);
-  border-color: rgba(255, 255, 255, 0.15);
+  background: var(--color-surface-3);
+  border-color: var(--color-surface-3);
 }
 
 .scenario-item input[type="radio"] {
@@ -2246,12 +2251,12 @@ body {
 .scenario-item__name {
   flex: 1;
   font-size: 14px;
-  color: rgba(255, 255, 255, 0.9);
+  color: var(--color-text);
 }
 
 .scenario-item__desc {
   font-size: 12px;
-  color: rgba(255, 255, 255, 0.5);
+  color: var(--color-text-muted);
   margin-top: 2px;
 }
 
@@ -2284,28 +2289,31 @@ body {
 .scenario-action-btn {
   padding: 4px 8px;
   background: transparent;
-  border: 1px solid rgba(255, 255, 255, 0.1);
-  border-radius: 4px;
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
   font-size: 14px;
+  color: var(--color-text-muted);
   cursor: pointer;
-  transition: all 0.2s;
+  transition: all var(--transition-fast);
 }
 
 .scenario-action-btn:hover {
-  background: rgba(255, 255, 255, 0.08);
-  border-color: rgba(255, 255, 255, 0.2);
+  background: var(--color-surface-2);
+  border-color: var(--color-surface-3);
+  color: var(--color-text);
 }
 
 .scenario-action-btn--confirm {
-  background: rgba(248, 113, 113, 0.15);
-  border-color: rgba(248, 113, 113, 0.3);
+  background: rgba(248, 113, 113, 0.1);
+  border-color: rgba(248, 113, 113, 0.2);
+  color: var(--color-error);
 }
 
 .scenario-empty {
   padding: 16px;
   text-align: center;
   font-size: 13px;
-  color: rgba(255, 255, 255, 0.4);
+  color: var(--color-text-muted);
   font-style: italic;
 }
 
@@ -2314,17 +2322,17 @@ body {
   margin-left: auto;
   padding: 4px 12px;
   font-size: 12px;
-  background: rgba(196, 97, 47, 0.15);
-  border: 1px solid rgba(196, 97, 47, 0.3);
+  background: rgba(59, 130, 246, 0.08);
+  border: 1px solid rgba(59, 130, 246, 0.2);
   border-radius: 999px;
-  color: #C4612F;
+  color: var(--color-primary);
   cursor: pointer;
-  transition: all 0.2s;
+  transition: all var(--transition-fast);
 }
 
 .config-create-btn:hover {
-  background: rgba(196, 97, 47, 0.25);
-  border-color: rgba(196, 97, 47, 0.5);
+  background: rgba(59, 130, 246, 0.16);
+  border-color: rgba(59, 130, 246, 0.4);
 }
 
 .config-group__title {
@@ -2340,25 +2348,30 @@ body {
   left: 0;
   right: 0;
   bottom: 0;
-  background: rgba(0, 0, 0, 0.7);
+  background: rgba(10, 10, 15, 0.45);
   display: flex;
   align-items: center;
   justify-content: center;
   z-index: 10000;
   backdrop-filter: blur(4px);
+  -webkit-backdrop-filter: blur(4px);
   animation: fadeIn 0.2s;
 }
 
+[data-theme="light"] .modal-overlay {
+  background: rgba(0, 0, 0, 0.3);
+}
+
 .modal {
-  background: #1F2421;
-  border: 1px solid rgba(255, 255, 255, 0.1);
-  border-radius: 12px;
+  background: var(--color-surface);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius);
   width: 90%;
   max-width: 600px;
   max-height: 85vh;
   display: flex;
   flex-direction: column;
-  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
+  box-shadow: 0 16px 48px rgba(10, 10, 15, 0.25);
   animation: slideUp 0.3s;
 }
 
@@ -2371,20 +2384,21 @@ body {
   align-items: center;
   justify-content: space-between;
   padding: 20px 24px;
-  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
+  border-bottom: 1px solid var(--color-border);
 }
 
 .modal__title {
   font-size: 18px;
-  font-weight: 500;
-  color: rgba(255, 255, 255, 0.95);
+  font-weight: 600;
+  color: var(--color-text);
+  letter-spacing: -0.01em;
 }
 
 .modal__close {
   background: transparent;
   border: none;
-  font-size: 24px;
-  color: rgba(255, 255, 255, 0.6);
+  font-size: 20px;
+  color: var(--color-text-muted);
   cursor: pointer;
   padding: 0;
   width: 32px;
@@ -2392,13 +2406,13 @@ body {
   display: flex;
   align-items: center;
   justify-content: center;
-  border-radius: 6px;
-  transition: all 0.2s;
+  border-radius: var(--radius-sm);
+  transition: all var(--transition-fast);
 }
 
 .modal__close:hover {
-  background: rgba(255, 255, 255, 0.08);
-  color: rgba(255, 255, 255, 0.9);
+  background: var(--color-surface-2);
+  color: var(--color-text);
 }
 
 .modal__body {
@@ -2412,7 +2426,7 @@ body {
   gap: 12px;
   justify-content: flex-end;
   padding-top: 16px;
-  border-top: 1px solid rgba(255, 255, 255, 0.08);
+  border-top: 1px solid var(--color-border);
   margin-top: 8px;
 }
 
@@ -2427,12 +2441,12 @@ body {
   gap: 8px;
   font-size: 14px;
   font-weight: 500;
-  color: rgba(255, 255, 255, 0.85);
+  color: var(--color-text);
   margin-bottom: 8px;
 }
 
 .form-required {
-  color: #C4612F;
+  color: var(--color-primary);
 }
 
 .form-input,
@@ -2440,21 +2454,28 @@ body {
 .form-select {
   width: 100%;
   padding: 10px 12px;
-  background: rgba(255, 255, 255, 0.05);
-  border: 1px solid rgba(255, 255, 255, 0.1);
-  border-radius: 6px;
-  color: rgba(255, 255, 255, 0.9);
+  background: var(--color-surface-2);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
+  color: var(--color-text);
   font-size: 14px;
   font-family: inherit;
-  transition: all 0.2s;
+  transition: all var(--transition-fast);
+}
+
+.form-input::placeholder,
+.form-textarea::placeholder {
+  color: var(--color-text-muted);
+  opacity: 0.7;
 }
 
 .form-input:focus,
 .form-textarea:focus,
 .form-select:focus {
   outline: none;
-  border-color: rgba(196, 97, 47, 0.5);
-  background: rgba(255, 255, 255, 0.08);
+  border-color: var(--color-primary);
+  background: var(--color-surface);
+  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
 }
 
 .form-textarea {
@@ -2468,15 +2489,15 @@ body {
   display: block;
   margin-top: 4px;
   font-size: 12px;
-  color: rgba(255, 255, 255, 0.4);
+  color: var(--color-text-muted);
 }
 
 .form-error {
   padding: 12px;
-  background: rgba(248, 113, 113, 0.15);
-  border: 1px solid rgba(248, 113, 113, 0.3);
-  border-radius: 6px;
-  color: #f87171;
+  background: rgba(248, 113, 113, 0.08);
+  border: 1px solid rgba(248, 113, 113, 0.2);
+  border-radius: var(--radius-sm);
+  color: var(--color-error);
   font-size: 13px;
   margin-top: 12px;
 }
@@ -2496,129 +2517,112 @@ body {
   align-items: center;
   justify-content: center;
   font-size: 22px;
-  background: rgba(255, 255, 255, 0.03);
-  border: 1px solid rgba(255, 255, 255, 0.1);
-  border-radius: 8px;
+  background: var(--color-surface-2);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
   cursor: pointer;
-  transition: all 0.2s;
+  transition: all var(--transition-fast);
 }
 
 .icon-picker__item:hover {
-  background: rgba(255, 255, 255, 0.08);
-  border-color: rgba(255, 255, 255, 0.2);
+  background: var(--color-surface-3);
+  border-color: var(--color-surface-3);
   transform: scale(1.05);
 }
 
 .icon-picker__item--active {
-  background: rgba(196, 97, 47, 0.2);
-  border-color: rgba(196, 97, 47, 0.5);
+  background: rgba(59, 130, 246, 0.1);
+  border-color: rgba(59, 130, 246, 0.4);
+  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.15);
 }
 
 /* Prompt guide */
 .form-guide-btn {
   background: transparent;
   border: none;
-  color: #C4612F;
+  color: var(--color-primary);
   font-size: 12px;
   cursor: pointer;
   padding: 4px 8px;
-  border-radius: 4px;
+  border-radius: var(--radius-sm);
   margin-left: auto;
-  transition: all 0.2s;
+  transition: all var(--transition-fast);
 }
 
 .form-guide-btn:hover {
-  background: rgba(196, 97, 47, 0.1);
+  background: rgba(59, 130, 246, 0.06);
 }
 
 .form-guide {
-  background: rgba(255, 255, 255, 0.03);
-  border: 1px solid rgba(255, 255, 255, 0.08);
-  border-radius: 8px;
+  background: var(--color-surface-2);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
   padding: 16px;
   margin-bottom: 12px;
   font-size: 13px;
   line-height: 1.6;
+  color: var(--color-text);
 }
 
 .form-guide strong {
-  color: rgba(255, 255, 255, 0.9);
+  color: var(--color-text);
 }
 
 .form-guide ul {
   margin: 8px 0;
   padding-left: 20px;
-  color: rgba(255, 255, 255, 0.7);
+  color: var(--color-text-muted);
 }
 
 .form-guide__code {
-  background: rgba(0, 0, 0, 0.3);
-  border: 1px solid rgba(255, 255, 255, 0.1);
-  border-radius: 6px;
+  background: var(--color-surface-3);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
   padding: 12px;
   margin-top: 8px;
   overflow-x: auto;
   font-size: 12px;
   line-height: 1.5;
-  color: rgba(255, 255, 255, 0.8);
+  color: var(--color-text);
 }
 
-/* Buttons */
-.btn {
+/* Buttons (modal-scoped overrides — only affect modal context) */
+.modal .btn {
   padding: 10px 20px;
-  border-radius: 6px;
+  border-radius: var(--radius-sm);
   font-size: 14px;
-  font-weight: 500;
+  font-weight: 600;
   cursor: pointer;
-  transition: all 0.2s;
+  transition: all var(--transition-fast);
   border: 1px solid transparent;
 }
 
-.btn:disabled {
+.modal .btn:disabled {
   opacity: 0.5;
   cursor: not-allowed;
 }
 
-.btn--primary {
-  background: #C4612F;
+.modal .btn--primary {
+  background: var(--color-primary);
   color: white;
-  border-color: #C4612F;
+  border-color: var(--color-primary);
 }
 
-.btn--primary:hover:not(:disabled) {
-  background: #A94E22;
-  border-color: #A94E22;
+.modal .btn--primary:hover:not(:disabled) {
+  background: var(--color-primary-hover);
+  border-color: var(--color-primary-hover);
 }
 
-.btn--secondary {
-  background: transparent;
-  color: rgba(255, 255, 255, 0.7);
-  border-color: rgba(255, 255, 255, 0.2);
+.modal .btn--secondary {
+  background: var(--color-surface-2);
+  color: var(--color-text-muted);
+  border-color: var(--color-border);
 }
 
-.btn--secondary:hover:not(:disabled) {
-  background: rgba(255, 255, 255, 0.08);
-  border-color: rgba(255, 255, 255, 0.3);
-  color: rgba(255, 255, 255, 0.9);
+.modal .btn--secondary:hover:not(:disabled) {
+  background: var(--color-surface-3);
+  border-color: var(--color-surface-3);
+  color: var(--color-text);
 }
 
-/* Animations */
-@keyframes fadeIn {
-  from {
-    opacity: 0;
-  }
-  to {
-    opacity: 1;
-  }
-}
-
-@keyframes slideUp {
-  from {
-    transform: translateY(20px);
-    opacity: 0;
-  }
-  to {
-    transform: translateY(0);
-    opacity: 1;
-  }
-}
+/* Animations — fadeIn & slideUp defined in main animation section above */