UI polishes, file chooser

src/styles/campaign-workspace.css

@@ -829,3 +829,92 @@
   .recipient-editor-table td:nth-child(2) { min-width: 300px; }
   .recipient-address-stack { min-width: 260px; }
 }
+
+/* Attachment file chooser panel embedded in the shared rules editor. */
+.attachment-rules-editor {
+  display: grid;
+  gap: 12px;
+  min-width: 0;
+}
+.attachment-rules-editor.has-file-browser {
+  grid-template-columns: minmax(0, 1fr) minmax(280px, 360px);
+  align-items: start;
+}
+.attachment-rules-main {
+  min-width: 0;
+}
+.attachment-rules-table tr.is-choosing-file td {
+  background: var(--panel-soft);
+}
+.attachment-rules-footer-actions {
+  margin-top: 12px;
+}
+.attachment-file-browser-panel {
+  display: grid;
+  gap: 12px;
+  border: 1px solid var(--line);
+  border-radius: 12px;
+  background: var(--panel-soft);
+  padding: 14px;
+  min-width: 0;
+}
+.attachment-file-browser-header {
+  display: flex;
+  justify-content: space-between;
+  gap: 12px;
+  align-items: start;
+}
+.attachment-file-browser-header h3 {
+  margin: 0 0 4px;
+  font-size: 15px;
+}
+.attachment-file-browser-list {
+  display: grid;
+  gap: 8px;
+}
+.attachment-file-browser-list .btn {
+  justify-content: flex-start;
+  text-align: left;
+  white-space: normal;
+}
+.attachment-file-browser-actions {
+  justify-content: flex-end;
+}
+
+@media (max-width: 1100px) {
+  .attachment-rules-editor.has-file-browser {
+    grid-template-columns: 1fr;
+  }
+}
+
+/* Chooser-backed readonly fields: legible, clickable display values without a text caret. */
+.chooser-display-input,
+.field-with-action input.chooser-display-input {
+  background: var(--panel-soft);
+  border-color: var(--line-dark);
+  color: var(--ink);
+  cursor: pointer;
+  caret-color: transparent;
+  user-select: none;
+}
+
+.chooser-display-input:hover,
+.field-with-action input.chooser-display-input:hover {
+  background: var(--panel);
+  border-color: var(--accent);
+}
+
+.chooser-display-input:focus,
+.field-with-action input.chooser-display-input:focus {
+  outline: none;
+  box-shadow: 0 0 0 2px rgba(239, 107, 58, .16);
+}
+
+.chooser-display-input:disabled,
+.field-with-action input.chooser-display-input:disabled {
+  background: var(--panel-soft);
+  border-color: var(--line);
+  color: var(--muted);
+  cursor: not-allowed;
+  opacity: 1;
+}