* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  text-align: center;
  font-family: 'Arial', sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  color: white;
  padding: 10px;
  transition: all 0.3s ease;
  overflow-x: hidden;
}

h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  margin: 15px 0;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
  letter-spacing: 2px;
}

h2 {
  font-size: clamp(1.1rem, 3vw, 1.5rem);
  margin: 15px auto;
  min-height: clamp(60px, 15vw, 80px);
  display: block;
  text-align: center;
  max-width: min(700px, 95vw);
  line-height: 1.5;
  padding: 10px 15px;
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.game-info {
  display: flex;
  justify-content: center;
  gap: clamp(15px, 4vw, 30px);
  margin: 15px 0;
  flex-wrap: wrap;
}

.score-display,
.high-score-display {
  background: rgba(255, 255, 255, 0.2);
  padding: clamp(8px, 2vw, 10px) clamp(15px, 4vw, 20px);
  border-radius: 10px;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.3);
  font-size: clamp(0.9rem, 2.5vw, 1rem);
}

.btn {
  height: clamp(120px, 20vw, 180px);
  width: clamp(120px, 20vw, 180px);
  border-radius: 25px;
  border: clamp(4px, 1vw, 8px) solid rgba(255, 255, 255, 0.3);
  margin: clamp(8px, 2vw, 15px);
  cursor: pointer;
  position: relative;
  transition: all 0.2s ease;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
  user-select: none;
}

.btn:hover {
  transform: scale(1.05);
  border-color: rgba(255, 255, 255, 0.6);
}

.btn:active,
.btn:focus {
  transform: scale(0.95);
  outline: none;
}

.btn-container {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  margin: clamp(20px, 5vw, 30px) 0;
  max-width: 100vw;
  overflow: hidden;
}

.line-one,
.line-two {
  display: flex;
  justify-content: center;
}

.yellow {
  background: linear-gradient(135deg, #ffeaa7, #fdcb6e);
}

.red {
  background: linear-gradient(135deg, #fd79a8, #e84393);
}

.purple {
  background: linear-gradient(135deg, #a29bfe, #6c5ce7);
}

.green {
  background: linear-gradient(135deg, #55efc4, #00cec9);
}

.flash {
  background: #ffffff !important;
  box-shadow: 0 0 50px rgba(255, 255, 255, 1), 0 0 80px rgba(255, 255, 255, 0.8), inset 0 0 30px rgba(255, 255, 255, 0.9);
  transform: scale(1.1);
  border-color: #ffffff !important;
}

.userflash {
  background: linear-gradient(135deg, #00ff88, #00cc66) !important;
  box-shadow: 0 0 25px rgba(0, 255, 136, 0.6);
  transform: scale(1.05);
}

.game-over {
  background: linear-gradient(135deg, #ff3742, #c44569) !important;
  animation: redFlash 0.4s ease-in-out 4;
}

@keyframes redFlash {

  0%,
  100% {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) !important;
  }

  50% {
    background: linear-gradient(135deg, #ff3742, #c44569) !important;
  }
}

.start-button {
  background: linear-gradient(135deg, #74b9ff, #0984e3);
  color: white;
  border: none;
  padding: clamp(12px, 3vw, 15px) clamp(25px, 6vw, 30px);
  font-size: clamp(1rem, 2.5vw, 1.2rem);
  border-radius: 50px;
  cursor: pointer;
  margin: clamp(20px, 5vw, 30px) auto;
  display: block;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
  min-width: clamp(140px, 30vw, 160px);
}

.start-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
}

.difficulty-selector {
  margin: 15px 0;
}

.difficulty-selector select {
  background: rgba(255, 255, 255, 0.2);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.3);
  padding: clamp(8px, 2vw, 10px) clamp(15px, 4vw, 20px);
  border-radius: 25px;
  font-size: clamp(0.9rem, 2.5vw, 1rem);
  backdrop-filter: blur(10px);
  max-width: 200px;
}

.difficulty-selector option {
  background: #667eea;
  color: white;
}

.pulse {
  animation: pulse 0.6s ease-in-out;
}

@keyframes pulse {
  0% {
    transform: scale(1);
  }

  50% {
    transform: scale(1.1);
  }

  100% {
    transform: scale(1);
  }
}

.fade-in {
  animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Mobile devices */
@media (max-width: 480px) {
  body {
    padding: 5px;
  }

  h1 {
    font-size: 2rem;
    margin: 10px 0;
    letter-spacing: 1px;
  }

  h2 {
    font-size: 1.1rem;
    margin: 10px auto;
    padding: 8px 10px;
    min-height: 50px;
  }

  .btn {
    height: 100px;
    width: 100px;
    margin: 5px;
    border-radius: 15px;
    border-width: 3px;
  }

  .game-info {
    gap: 10px;
    margin: 10px 0;
  }

  .score-display,
  .high-score-display {
    padding: 6px 12px;
    font-size: 0.85rem;
  }

  .start-button {
    padding: 10px 20px;
    font-size: 0.95rem;
    margin: 15px auto;
    min-width: 120px;
  }

  .difficulty-selector select {
    padding: 6px 12px;
    font-size: 0.85rem;
  }
}

/* Tablets */
@media (min-width: 481px) and (max-width: 768px) {
  .btn {
    height: 140px;
    width: 140px;
    margin: 8px;
    border-radius: 20px;
  }

  h1 {
    font-size: 2.5rem;
  }

  h2 {
    font-size: 1.3rem;
    margin: 15px auto;
    padding: 10px 15px;
    min-height: 60px;
  }

  .game-info {
    gap: 20px;
  }

  .start-button {
    margin: 20px auto;
    padding: 12px 25px;
    font-size: 1.1rem;
  }
}

/* Small laptops */
@media (min-width: 769px) and (max-width: 1024px) {
  .btn {
    height: 160px;
    width: 160px;
    margin: 12px;
  }

  h1 {
    font-size: 2.8rem;
  }

  h2 {
    font-size: 1.4rem;
  }
}

/* Desktops */
@media (min-width: 1025px) {
  body {
    padding: 20px;
  }

  .btn {
    height: 180px;
    width: 180px;
    margin: 15px;
  }

  h1 {
    font-size: 3rem;
    margin: 20px 0;
  }

  h2 {
    font-size: 1.5rem;
    margin: 20px auto;
    padding: 10px 20px;
  }

  .game-info {
    gap: 30px;
    margin: 20px 0;
  }
}

/* Mobile landscape */
@media (max-height: 600px) and (orientation: landscape) {
  h1 {
    font-size: 1.8rem;
    margin: 5px 0;
  }

  h2 {
    font-size: 1rem;
    margin: 5px auto;
    min-height: 40px;
  }

  .btn {
    height: 80px;
    width: 80px;
    margin: 4px;
  }

  .btn-container {
    margin: 10px 0;
  }

  .game-info {
    margin: 5px 0;
  }

  .start-button {
    padding: 8px 16px;
    margin: 10px auto;
  }
}

/* Touch device optimizations */
@media (hover: none) and (pointer: coarse) {
  .btn:hover {
    transform: none;
  }

  .btn:active {
    transform: scale(0.9);
    transition: transform 0.1s ease;
  }

  .btn {
    touch-action: manipulation;
  }
}