cherry-pick #5: theme QSS refinements (eb80c07f57)

Resolved conflicts: kept HEAD versions of QSS (has later refinements),
InitGui.py (has newer origin architecture), and silo submodule.

resources/preferences/KindredCreate/KindredCreate.qss

@@ -247,8 +247,9 @@ QDockWidget {
 QDockWidget::title {
     background-color: #181825;
     color: #cdd6f4;
-    padding: 6px;
+    padding: 8px 6px;
     border-bottom: 1px solid #313244;
+    min-height: 18px;
 }
 
 QDockWidget::close-button,
@@ -757,6 +758,16 @@ QTreeView::branch:selected {
     background-color: #45475a;
 }
 
+QTreeView::branch:has-children:!has-siblings:closed,
+QTreeView::branch:closed:has-children:has-siblings {
+    image: url(qss:images_dark-light/branch_closed.svg);
+}
+
+QTreeView::branch:open:has-children:!has-siblings,
+QTreeView::branch:open:has-children:has-siblings {
+    image: url(qss:images_dark-light/branch_open.svg);
+}
+
 /* =============================================================================
    List View
    ============================================================================= */
@@ -830,6 +841,7 @@ QHeaderView::section {
     border-right: 1px solid #45475a;
     border-bottom: 1px solid #45475a;
     padding: 6px 8px;
+    min-height: 20px;
 }
 
 QHeaderView::section:hover {
@@ -1103,7 +1115,8 @@ QSint--ActionGroup QToolButton {
     color: #cdd6f4;
     border: none;
     border-radius: 4px;
-    padding: 6px;
+    padding: 8px 6px;
+    min-height: 18px;
 }
 
 QSint--ActionGroup QToolButton:hover {
@@ -1151,6 +1164,16 @@ SpreadsheetGui--SheetTableView QHeaderView::section {
     padding: 4px;
 }
 
+/* Spreadsheet cell editor - reduce padding for better text visibility */
+SpreadsheetGui--SheetTableView QLineEdit {
+    background-color: #313244;
+    color: #cdd6f4;
+    border: 1px solid #cba6f7;
+    border-radius: 0px;
+    padding: 1px 2px;
+    margin: 0px;
+}
+
 /* Python Console */
 Gui--PythonConsole {
     background-color: #11111b;