* {
  box-sizing: border-box;
  font-family: Arial, sans-serif;
}

body {
  background: #0f172a;
  color: #fff;
  text-align: center;
}

h1 {
  margin: 20px 0;
}

.game-container {
  max-width: 520px;
  margin: auto;
  display: grid;
  gap: 10px;
}

.card {
  aspect-ratio: 1 / 1;
  width: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s;
  cursor: pointer;
}

.card.flip {
  transform: rotateY(180deg);
}

.card div {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 32px;
  backface-visibility: hidden;
}

.front {
  background: #334155;
}

.back {
  background: #22c55e;
  transform: rotateY(180deg);
}

/* ✨ MATCH GLOW */
.card.match {
  animation: glow 0.6s ease;
}

@keyframes glow {
  0% {
    box-shadow: 0 0 0px #22c55e;
  }
  50% {
    box-shadow: 0 0 20px #22c55e;
  }
  100% {
    box-shadow: 0 0 0px #22c55e;
  }
}

/* ❌ MISMATCH SHAKE */
.card.shake {
  animation: shake 0.4s;
}

@keyframes shake {
  0% { transform: translateX(0) rotateY(180deg); }
  25% { transform: translateX(-6px) rotateY(180deg); }
  50% { transform: translateX(6px) rotateY(180deg); }
  75% { transform: translateX(-6px) rotateY(180deg); }
  100% { transform: translateX(0) rotateY(180deg); }
}


/*==================
CSS BUTTON GLOBAL
==================*/
button {
  margin-bottom: 20px;
  padding: 10px 18px;
  border: none;
  border-radius: 8px;
  background: #22c55e;
  color: #0f172a;
  font-size: 16px;
  cursor: pointer;
  font-weight: bold;
}

button:hover {
  background: #16a34a;
}

select {
  padding: 8px 14px;
  border-radius: 8px;
  border: none;
  margin-bottom: 15px;
  font-size: 15px;
}

#soundToggle {
  margin-bottom: 10px;
  background: #334155;
  color: #fff;
}

/*==================
INFO BAR STYLE
==================*/
.info {
  display: flex;
  justify-content: center;
  gap: 30px;
  margin-bottom: 20px;
  font-size: 18px;
}

.best {
  margin-bottom: 20px;
  font-size: 15px;
  opacity: 0.85;
}


/*==================
MODAL STYLE
==================*/
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.modal.hidden {
  display: none;
}

.modal-content {
  background: #020617;
  padding: 30px;
  border-radius: 12px;
  text-align: center;
  width: 280px;
  animation: pop 0.3s ease;
}

.modal-content h2 {
  margin-bottom: 10px;
}

.modal-content button {
  margin-top: 15px;
}

@keyframes pop {
  from {
    transform: scale(0.8);
    opacity: 0;
  }
  to {
    transform: scale(1);
    opacity: 1;
  }
}