use raw time values independent of timebase for scaling timeline ui

app/ui/style/olive-dark/style.css

@@ -73,3 +73,9 @@ NodeViewItemWidget {
   qproperty-titlebarColor: #4040a0;
   qproperty-borderColor: #000000;
 }
+
+/* Timeline playhead styling */
+TimelinePlayhead {
+  qproperty-playheadColor: #ff0000;
+  qproperty-playheadHighlightColor: rgba(255, 255, 255, 0.33);
+}

app/ui/style/olive-light/style.css

@@ -72,4 +72,10 @@ QTreeView, QListView, QLineEdit, QMenu, QProgressBar, QPushButton::checked, Node
 NodeViewItemWidget {
   qproperty-titlebarColor: #a0a0ff;
   qproperty-borderColor: #000000;
-}
+}
+
+/* Timeline playhead styling */
+TimelinePlayhead {
+  qproperty-playheadColor: #ff0000;
+  qproperty-playheadHighlightColor: rgba(0, 0, 0, 0.25);
+}