fix: 优化后台工单工作区布局

frontend/src/admin/theme.css

@@ -32,6 +32,77 @@ body {
 [data-theme="dark"] ::-webkit-scrollbar-thumb { background: #49454f; }
 [data-theme="dark"] ::-webkit-scrollbar-thumb:hover { background: #938f99; }
 
+/* 工单工作区：占满 AdminLayout 内容区，桌面保持列表/详情主次比例。 */
+.ticket-workspace {
+  width: 100%;
+  max-width: none;
+  min-width: 0;
+  min-height: calc(100vh - 112px);
+}
+
+.ticket-workspace .ticket-stats {
+  width: 100%;
+}
+
+.ticket-work-area {
+  display: grid;
+  grid-template-columns: minmax(280px, 0.55fr) minmax(0, 1fr);
+  gap: 16px;
+  width: 100%;
+  min-width: 0;
+  min-height: calc(100vh - 280px);
+  align-items: stretch;
+}
+
+.ticket-list-pane,
+.ticket-detail-pane {
+  min-width: 0;
+  width: 100%;
+}
+
+.ticket-list-pane > .MuiPaper-root,
+.ticket-detail-pane > .MuiPaper-root {
+  width: 100%;
+  min-width: 0;
+  box-sizing: border-box;
+}
+
+.ticket-list-pane > .MuiPaper-root {
+  min-height: calc(100vh - 280px);
+}
+
+.ticket-detail-pane > .MuiPaper-root {
+  min-height: calc(100vh - 280px);
+}
+
+@media (max-width: 1199px) and (min-width: 700px) {
+  .ticket-work-area {
+    grid-template-columns: minmax(250px, 0.62fr) minmax(0, 1fr);
+    gap: 14px;
+  }
+}
+
+@media (max-width: 699px) {
+  .ticket-workspace {
+    min-height: 0;
+  }
+
+  .ticket-work-area {
+    grid-template-columns: minmax(0, 1fr);
+    min-height: 0;
+    gap: 16px;
+  }
+
+  .ticket-list-pane > .MuiPaper-root,
+  .ticket-detail-pane > .MuiPaper-root {
+    min-height: 0;
+  }
+
+  .ticket-detail-pane > .MuiPaper-root {
+    min-height: 480px;
+  }
+}
+
 /* 减弱动效偏好 */
 @media (prefers-reduced-motion: reduce) {
   *, *::before, *::after {