/* ===== 素数ハント ===== */

.ph-info {
  font-size: 0.85rem;
  font-weight: 600;
  color: rgba(255,255,255,0.65);
  text-align: center;
  margin: 4px 0;
}

.ph-stage {
  width: 100%;
  max-width: 400px;
  background: var(--card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 14px;
  box-sizing: border-box;
  margin: 6px 0;
}

.ph-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.ph-num-btn {
  height: 56px;
  font-size: 1.25rem;
  font-weight: 800;
  color: #fff;
  background: rgba(255,255,255,0.1);
  border: 2px solid rgba(255,255,255,0.15);
  border-radius: 10px;
  cursor: pointer;
  transition: transform 0.1s, background 0.1s, opacity 0.2s;
  user-select: none;
  -webkit-user-select: none;
}

.ph-num-btn:active {
  transform: scale(0.9);
}

.ph-num-btn.ph-tapped-correct {
  background: rgba(16,185,129,0.35);
  border-color: #10b981;
  color: #10b981;
  pointer-events: none;
  animation: phCorrect 0.25s ease both;
}

@keyframes phCorrect {
  50% { transform: scale(1.15); }
}

.ph-num-btn.ph-tapped-wrong {
  background: rgba(244,63,94,0.35);
  border-color: #f43f5e;
  color: #f43f5e;
  pointer-events: none;
  animation: phWrong 0.35s ease both;
}

@keyframes phWrong {
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
  100% { transform: translateX(0); }
}

.ph-num-btn.ph-pop {
  animation: phPop 0.2s cubic-bezier(0.175,0.885,0.32,1.275) both;
}

@keyframes phPop {
  0%   { transform: scale(0); opacity: 0; }
  70%  { transform: scale(1.08); }
  100% { transform: scale(1); opacity: 1; }
}