fix(export): use solid background for detail drawer

src/pages/ExportPage.scss

@@ -1031,7 +1031,7 @@
   height: calc(100vh - 40px);
   border-left: 1px solid var(--border-color);
   border-radius: 0;
-  background: var(--card-bg);
+  background: var(--bg-secondary-solid, #ffffff);
   display: flex;
   flex-direction: column;
   overflow: hidden;