Dark mode - replace redColor w/ systemRedColor

also replaced blackColor w/ nil.

Ample/DownloadWindowController.m

@@ -244,7 +244,7 @@ enum {
         [_downloadField setTextColor: nil];
     } else {
         _effectiveURL = [NSURL URLWithString: _downloadURL];
-        [_downloadField setTextColor: [NSColor redColor]];
+        [_downloadField setTextColor: [NSColor systemRedColor]];
     }
 }
 #endif

Ample/MediaViewController.m

@@ -225,7 +225,7 @@
    
 #if 0
     NSColor *tintColor = nil;
-    if (!_valid) tintColor = [NSColor redColor];
+    if (!_valid) tintColor = [NSColor systemRedColor];
     [button setContentTintColor: tintColor];
 #endif
 }

Ample/PreferencesWindowController.m

@@ -44,9 +44,9 @@
     NSFileManager * fm = [NSFileManager defaultManager];
 
     if ([path length] == 0 || [fm isExecutableFileAtPath: path]) {
-        [_pathField setTextColor: [NSColor blackColor]];
+        [_pathField setTextColor: nil];
     } else {
-        [_pathField setTextColor: [NSColor redColor]];
+        [_pathField setTextColor: [NSColor systemRedColor]];
     }
 }
 
@@ -55,16 +55,16 @@
     BOOL directory = YES;
     
     if ([path length] == 0) {
-        [_wdField setTextColor: [NSColor blackColor]];
+        [_wdField setTextColor: nil];
         return;
     }
     
     if ([fm fileExistsAtPath: path isDirectory: &directory] && directory) {
-        [_wdField setTextColor: [NSColor blackColor]];
+        [_wdField setTextColor: nil];
         return;
 
     }
-    [_wdField setTextColor: [NSColor redColor]];
+    [_wdField setTextColor: [NSColor systemRedColor]];
 }
 
 - (IBAction)pathChanged:(id)sender {

Ample/Transformers.m

@@ -67,7 +67,7 @@
 
 - (id)transformedValue:(id)value {
     BOOL valid = [(NSNumber *)value boolValue];
-    return valid ? nil : [NSColor redColor];
+    return valid ? nil : [NSColor systemRedColor];
 }
 
 @end