gtk: Revert titlebar colors only in standard variant

src/_sass/_colors.scss

@@ -112,8 +112,8 @@ $scrim-alt: rgba(black, .3);

                                
                                
                                
                            
                                
                                    
                                        
                                            112  
                                            $panel:                                 if($topbar == 'dark', #1F1F1F, $scrim);
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            113  
                                            $panel-solid:                           if($topbar == 'dark', #1F1F1F, #CCCCCC); // for Unity panel which doesn't allow translucent colors
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            114  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        115 -
                                        $titlebar:                              if($topbar == 'dark', $-dark-surface-4dp, #E0E0E0);
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        116 -
                                        $titlebar-backdrop:                     if($topbar == 'dark', $-dark-surface-1dp, #D6D6D6);
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        115 +
                                        $titlebar:                              if($topbar == 'dark', if($variant == 'light', #383838, $-dark-surface-4dp), #E0E0E0);
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        116 +
                                        $titlebar-backdrop:                     if($topbar == 'dark', if($variant == 'light', #303030, $-dark-surface-1dp), #D6D6D6);
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            117  
                                            $titlebar-indicator:                    if($topbar == 'dark', currentColor, $primary);
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            118  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            119  
                                            //