.c4-board {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  width: 100%;
  max-width: 520px;
  aspect-ratio: 7 / 6;
  margin: 0 auto;
  padding: 8px;
  background: #1f4ea8;
  border: 2px solid #11306b;
  border-radius: 10px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.4);
  gap: 6px;
  user-select: none;
}
.c4-cell {
  background: #0e1a30;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  cursor: pointer;
  aspect-ratio: 1;
  transition: background 80ms;
}
.c4-cell.col-hover {
  background: #18264a;
}
.disc {
  width: 86%;
  height: 86%;
  border-radius: 50%;
  box-shadow: inset 0 -4px 0 rgba(0,0,0,0.25), 0 1px 2px rgba(0,0,0,0.4);
}
.disc.yellow {
  background: radial-gradient(circle at 35% 30%, #ffe27a, #ffce3c 55%, #d99b00);
}
.disc.red {
  background: radial-gradient(circle at 35% 30%, #ff9a8a, #e0463a 55%, #8a1f17);
}
.disc.preview {
  opacity: 0.55;
  animation: c4-bob 1.4s ease-in-out infinite;
}
.disc.last {
  outline: 3px solid rgba(255,255,255,0.85);
  outline-offset: -3px;
}
@keyframes c4-bob {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-4px); }
}
.preview-row {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  width: 100%;
  max-width: 520px;
  margin: 0 auto 4px;
  padding: 0 8px;
  gap: 6px;
  aspect-ratio: 7 / 1;
}
.preview-slot {
  display: flex;
  align-items: center;
  justify-content: center;
}
.mp-player .dot.disc {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  display: inline-block;
  box-shadow: inset 0 -2px 0 rgba(0,0,0,0.25);
}