style: track buttons with border, rounded, 20px height, 14px font, red active

- Each button: border border-zinc-600 rounded-md, h-[20px], text-[14px]
- Active/play-on track: bg-red-700 (red), selected track: bg-yellow-600
- Off track: bg-zinc-800 text-zinc-500

app/static/js/app.jsx

@@ -6155,9 +6155,9 @@ const beatSec = 60.0 / (parseInt(bpm) || 120);
               return s.size === allIds.length ? null : s;
             });
           },
-          className: "w-full flex items-center justify-center h-[18px] border-b border-zinc-900 cursor-pointer outline-none " + (isActive ? 'bg-yellow-600 text-black font-bold border-l-2 border-l-yellow-300' : (isPlayOn ? 'bg-purple-700 text-white font-semibold border-l-2 border-l-purple-400' : 'bg-zinc-800 text-zinc-500 hover:bg-zinc-700 border-l-2 border-l-transparent'))
+          className: "w-full flex items-center justify-center h-[20px] border border-zinc-600 rounded-md cursor-pointer outline-none mx-1 my-[2px] " + (isActive ? 'bg-yellow-600 text-black font-bold' : (isPlayOn ? 'bg-red-700 text-white font-semibold' : 'bg-zinc-800 text-zinc-500 hover:bg-zinc-700'))
         }, React.createElement("span", {
-          className: "text-[12px] font-sans truncate px-1",
+          className: "text-[14px] font-sans truncate px-1",
           title: track ? track.name : m._trackName
         }, track ? track.name : m._trackName)));
       });