Improvements for Import UI (#4937)

* Fixed bug with old titles used in popup, improved UI for greater rename input size

* Added flexbox utility CSS and use it for import UI

themes/tiddlywiki/vanilla/base.tid

@@ -2032,11 +2032,6 @@ html body.tc-body.tc-single-tiddler-window {
 	width: 100%;
 }
 
-input.tc-import-rename {
-	width: 85%;
-	margin-right: 0.5em;
-}
-
 /*
 ** Alerts
 */
@@ -2775,6 +2770,31 @@ select {
 	fill: <<colour background>>;
 }
 
+/*
+** Flexbox utility classes
+*/
+
+.tc-flex {
+	display: -webkit-flex;
+	display: flex;
+}
+
+.tc-flex-column {
+	flex-direction: column;
+}
+
+.tc-flex-row {
+	flex-direction: row;
+}
+
+.tc-flex-grow-1 {
+	flex-grow: 1;
+}
+
+.tc-flex-grow-2 {
+	flex-grow: 2;
+}
+
 /*
 ** Other utility classes
 */