Nudge the logo off centre

The lettering does not sit in the middle of its own image, so centring
the image leaves the logo looking pushed to one side.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H9v2Xoa6eoeGYpK6gp95k9

public/player/player.css

@@ -49,7 +49,10 @@ body {
   position: fixed;
   top: 50%;
   left: 50%;
-  translate: -50% -50%;
+  /* Centred, then nudged sideways by LOGO_OFFSET, which backdrop.js writes
+     onto the element. */
+  --logo-shift: 0%;
+  translate: calc(-50% + var(--logo-shift)) -50%;
   height: auto;
   /* Only bites on a screen too short for the width above — on the projector
      the width is what decides. */