disable question fade when using software rendering

aqt/profiles.py

@@ -406,7 +406,8 @@ please see:
         return os.path.join(self.base, "gldriver")
 
     def glMode(self):
-        assert not isMac
+        if isMac:
+            return "auto"
 
         path = self._glPath()
         if not os.path.exists(path):

aqt/reviewer.py

@@ -119,12 +119,16 @@ class Reviewer:
 
     def revHtml(self):
         extra = self.mw.col.conf.get("reviewExtra", "")
+        qFade = 100
+        if self.mw.pm.glMode() == "software":
+            qFade = 0
         return """
 <div id=_mark>&#x2605;</div>
 <div id=_flag>&#x2691;</div>
 <div id=qa></div>
+<script>qFade={};</script>
 {}
-""".format(extra)
+""".format(qFade, extra)
 
     def _initWeb(self):
         self._reps = 0