/**
 * Modern Neon — dark futuristic with glowing neon accents.
 */
[data-theme="modern_neon"] {
  --cp-bg: #050510;
  --cp-fg: #e8f7ff;
  --cp-surface: #0d1024;
  --cp-border: #2a3a6a;
  --cp-muted: #8aa0c8;
  --cp-accent: #39ff14;
  --cp-accent-soft: rgba(57, 255, 20, 0.18);
  --cp-input-bg: #080814;
  --cp-square-light: #1a2240;
  --cp-square-dark: #0a0e22;
  --cp-board-shadow:
    0 0 0 1px #39ff14,
    0 0 18px rgba(57, 255, 20, 0.35),
    0 12px 32px rgba(0, 0, 0, 0.6);
  --cp-piece-filter: drop-shadow(0 0 4px #00e5ff);
}