style(web): 更新审批中心、审计、员工管理、请求列表页面的样式文件，增加内边距和调整布局间距

web/src/assets/styles/views/approval-center-view.css

@@ -77,12 +77,16 @@
 .hint { display: inline-flex; align-items: center; gap: 7px; margin-top: 10px; color: #64748b; font-size: 13px; }
 
 .table-wrap {
-  min-height: 0;
+  min-height: 400px;
   margin-top: 10px;
   overflow-x: auto;
   overflow-y: auto;
   border: 1px solid #edf2f7;
   border-radius: 10px;
+  background: linear-gradient(180deg, #fcfefd 0%, #f4f8f6 100%);
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
 
 table { width: 100%; min-width: 1180px; border-collapse: collapse; table-layout: fixed; }

web/src/assets/styles/views/audit-view.css

@@ -312,10 +312,14 @@
 .table-wrap {
   flex: 1 1 auto;
   position: relative;
-  min-height: 0;
+  min-height: 400px;
   overflow: auto;
   border: 1px solid #edf2f7;
   border-radius: 12px;
+  background: linear-gradient(180deg, #fcfefd 0%, #f4f8f6 100%);
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
 
 .table-state,

web/src/assets/styles/views/employee-management-view.css

@@ -324,12 +324,16 @@
 
 .table-wrap {
   flex: 1 1 auto;
-  min-height: 0;
+  min-height: 400px;
   overflow-x: auto;
   overflow-y: auto;
   margin-top: 10px;
   border: 1px solid #edf2f7;
   border-radius: 12px;
+  background: linear-gradient(180deg, #fcfefd 0%, #f4f8f6 100%);
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
 
 .list-foot {

web/src/assets/styles/views/requests-view.css

@@ -283,12 +283,16 @@
 }
 
 .table-wrap {
-  min-height: 0;
+  min-height: 400px;
   margin-top: 10px;
   overflow-x: auto;
   overflow-y: auto;
   border: 1px solid #edf2f7;
   border-radius: 10px;
+  background: linear-gradient(180deg, #fcfefd 0%, #f4f8f6 100%);
+  display: flex;
+  align-items: center;
+  justify-content: center;
 }
 
 .table-state {