Add foreground color to WinSeparator for visible split lines

lua/lush_theme/darcula_lush.lua

@@ -581,10 +581,10 @@ local theme =
       },
       Type {fg = colors.SyntaxForeground},
       Underlined {fg = colors.AccentForeground, gui = "underline"},
-      VertSplit {bg = colors.GutterBackground},
+      VertSplit {fg = colors.TabBackground, bg = colors.GutterBackground},
       Visual {bg = colors.SelectionBackground},
       WarningMsg {fg = colors.WarningForeground},
-      WinSeparator {bg = colors.GutterBackground},
+      WinSeparator {fg = colors.TabBackground, bg = colors.GutterBackground},
       --
       -- mason.nvim
       MasonBackdrop {bg = colors.Background},