feat: redesign admin layout and stats dashboards

admin-frontend/src/pages/UsersPage.vue

@@ -285,18 +285,22 @@ onMounted(refreshAll)
 .page-stack {
   display: flex;
   flex-direction: column;
-  gap: 12px;
+  gap: 14px;
+  min-width: 0;
 }
 
 .card {
   border-radius: var(--app-radius);
   border: 1px solid var(--app-border);
+  background: var(--app-card-bg);
+  box-shadow: var(--app-shadow-soft);
 }
 
 .section-title {
   margin: 0 0 12px;
-  font-size: 14px;
+  font-size: 15px;
   font-weight: 800;
+  letter-spacing: 0.2px;
 }
 
 .help {
@@ -306,6 +310,9 @@ onMounted(refreshAll)
 
 .table-wrap {
   overflow-x: auto;
+  border-radius: 10px;
+  border: 1px solid var(--app-border);
+  background: #fff;
 }
 
 .user-block {