qt StatusBarButton: use custom theme for macOS if using default theme

electrum/gui/qt/main_window.py

@@ -104,7 +104,9 @@ if TYPE_CHECKING:
 
 LN_NUM_PAYMENT_ATTEMPTS = 10
 
+
 class StatusBarButton(QToolButton):
+    # note: this class has a custom stylesheet applied in stylesheet_patcher.py
     def __init__(self, icon, tooltip, func):
         QToolButton.__init__(self)
         self.setText('')

electrum/gui/qt/stylesheet_patcher.py

@@ -2,32 +2,68 @@
 It reads the current stylesheet, appends our modifications and sets the new stylesheet.
 """
 
+import sys
+
 from PyQt5 import QtWidgets
 
 
+CUSTOM_PATCH_FOR_DARK_THEME = '''
+/* PayToEdit text was being clipped */
+QAbstractScrollArea {
+    padding: 0px;
+}
+/* In History tab, labels while edited were being clipped (Windows) */
+QAbstractItemView QLineEdit {
+    padding: 0px;
+    show-decoration-selected: 1;
+}
+/* Checked item in dropdowns have way too much height...
+   see #6281 and https://github.com/ColinDuquesnoy/QDarkStyleSheet/issues/200
+   */
+QComboBox::item:checked {
+    font-weight: bold;
+    max-height: 30px;
+}
+'''
+
+CUSTOM_PATCH_FOR_DEFAULT_THEME_MACOS = '''
+/* On macOS, main window status bar icons have ugly frame (see #6300) */
+StatusBarButton {
+    background-color: transparent;
+    border: 1px solid transparent;
+    border-radius: 4px;
+    margin: 0px;
+    padding: 2px;
+}
+StatusBarButton:checked {
+  background-color: transparent;
+  border: 1px solid #1464A0;
+}
+StatusBarButton:checked:disabled {
+  border: 1px solid #14506E;
+}
+StatusBarButton:pressed {
+  margin: 1px;
+  background-color: transparent;
+  border: 1px solid #1464A0;
+}
+StatusBarButton:disabled {
+  border: none;
+}
+StatusBarButton:hover {
+  border: 1px solid #148CD2;
+}
+'''
+
+
 def patch_qt_stylesheet(use_dark_theme: bool) -> None:
-    if not use_dark_theme:
-        return
+    custom_patch = ""
+    if use_dark_theme:
+        custom_patch = CUSTOM_PATCH_FOR_DARK_THEME
+    else:  # default theme (typically light)
+        if sys.platform == 'darwin':
+            custom_patch = CUSTOM_PATCH_FOR_DEFAULT_THEME_MACOS
 
     app = QtWidgets.QApplication.instance()
-
-    style_sheet = app.styleSheet()
-    style_sheet = style_sheet + '''
-    /* PayToEdit text was being clipped */
-    QAbstractScrollArea {
-        padding: 0px;
-    }
-    /* In History tab, labels while edited were being clipped (Windows) */
-    QAbstractItemView QLineEdit {
-        padding: 0px;
-        show-decoration-selected: 1;
-    }
-    /* Checked item in dropdowns have way too much height...
-       see #6281 and https://github.com/ColinDuquesnoy/QDarkStyleSheet/issues/200
-       */
-    QComboBox::item:checked {
-        font-weight: bold;
-        max-height: 30px;
-    }
-    '''
+    style_sheet = app.styleSheet() + custom_patch
     app.setStyleSheet(style_sheet)