fix(ui): unify dialogs and complete theme component coverage

frontend/src/assets/themes/paper-moments.theme

@@ -1,6 +1,6 @@
 theme_id: paper-moments
 name: 纸间时光 · Paper Moments
-version: 1.6.1
+version: 1.6.2
 author: NotesAgent
 description: 奶油纸张、手帐虚线与粉蓝胶带，把每天的灵感好好收藏。
 min_app_version: 0.2.0
@@ -318,3 +318,7 @@ license: MIT
 @supports (appearance: base-select) {
   [data-theme="paper-moments"] ::picker(select) { border: 1px solid #b5a693; outline: 1px dashed #d5c8b5; outline-offset: -4px; background: #fffdf5; box-shadow: var(--shadow-md); }
 }
+
+/* Nested choices retain a quiet paper border without repeating tape/shadows. */
+[data-theme="paper-moments"] .surface-nested { border: 1px dashed #c5b9a7; background: #fffdf5; border-radius: 6px; }
+[data-theme="paper-moments"] .surface-nested.selected { border-color: var(--color-accent-primary); background: var(--color-accent-soft); }