feat(marquee): readable 2s peak hold + cross-fade, keep <=3 bright

public/css/main.css

@@ -5537,10 +5537,9 @@ body.content-edit-shift-active.content-edit-mode-active .content-edit-fab-stack
 
 @keyframes tagFlicker {
   0%   { opacity: 1; }
-  4%   { opacity: 1; }
-  13%  { opacity: 0.2; }
-  87%  { opacity: 0.2; }
-  96%  { opacity: 1; }
+  14%  { opacity: 1; }
+  19%  { opacity: 0.2; }
+  95%  { opacity: 0.2; }
   100% { opacity: 1; }
 }