update 优化 前端样式初步调整并删除无用样式

src/assets/styles/components/_page-shell.scss

@@ -6,14 +6,7 @@
   gap: 12px;
 }
 
-.page-shell {
-  display: flex;
-  flex-direction: column;
-  gap: 12px;
-}
-
-.app-main > .page-shell,
-.app-main > .page-shell.p-2 {
+.app-main > .p-2 {
   padding: 0 !important;
   margin: 0 !important;
 }
@@ -26,15 +19,7 @@
   margin-bottom: 0 !important;
 }
 
-.page-shell > .el-row,
-.page-shell > .el-card,
-.page-shell > .search-wrap,
-.page-shell > div,
-.page-shell > section {
-  margin-bottom: 0 !important;
-}
-
-/* Scoped mixins for CRUD pages so view-level styles stay focused on page-specific rules. */
+// --- CRUD / 树表页用混入（在 .vue 内 @use 后 @include） ---
 
 @mixin action-link-buttons($background: rgba(53, 109, 255, 0.08)) {
   .data-table {