:root {
  --primary-bg: #ffffff;
  --secondary-bg: #f5f5f5;
  --primary-text: #000000;
  --secondary-text: #808080;
  --border-color: #000000;
  --shadow-color: #808080;
  --card-back-bg: #000000;
  --card-front-bg: #ffffff;
  --accent-bg: #808080;
  --hint-color: #ff6b6b;
  --hover-shadow: 8px 8px 0;
  --normal-shadow: 4px 4px 0;
  --border-width: 3px;
  --card-size: min(12vw, 80px);
  --gap-size: clamp(8px, 2vw, 16px);
}

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

body {
  background: var(--primary-bg);
  font-family: "Arial Black", Arial, sans-serif;
  color: var(--primary-text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: clamp(10px, 2vw, 15px);
  overflow-x: hidden;
}

/* Navigation Bar - Minimal Height */
.nav-bar {
  width: 100%;
  background: var(--primary-text);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--normal-shadow) var(--shadow-color);
  padding: clamp(8px, 1.5vw, 12px) clamp(12px, 2vw, 16px);
  margin-bottom: clamp(15px, 3vh, 25px);
  flex-shrink: 0;
}

.nav-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: clamp(8px, 2vw, 12px);
}

.logo {
  font-size: clamp(1rem, 3vw, 1.4rem);
  font-weight: 900;
  color: var(--primary-bg);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.nav-buttons {
  display: flex;
  gap: clamp(6px, 1.5vw, 10px);
  flex-wrap: wrap;
}

.nav-btn {
  background: var(--primary-bg);
  color: var(--primary-text);
  border: 2px solid var(--border-color);
  padding: clamp(4px, 1vw, 6px) clamp(8px, 2vw, 12px);
  font-size: clamp(0.6rem, 1.5vw, 0.8rem);
  font-weight: 900;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: all 0.2s;
  box-shadow: 2px 2px 0 var(--shadow-color);
  text-decoration: none;
  display: inline-block;
}

.nav-btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: 3px 3px 0 var(--shadow-color);
}

/* Main Game Layout - Responsive */
.game-layout {
  flex: 1;
  display: flex;
  gap: clamp(15px, 3vw, 30px);
  align-items: flex-start;
  justify-content: center;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
}

/* Game Stats - Left Side on Desktop */
.stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap-size);
  width: 100%;
  max-width: 200px;
  min-width: 150px;
}

.stat-item {
  background: var(--primary-text);
  color: var(--primary-bg);
  padding: clamp(8px, 2vw, 12px);
  border: var(--border-width) solid var(--border-color);
  text-align: center;
  box-shadow: var(--normal-shadow) var(--shadow-color);
}

.stat-label {
  font-size: clamp(0.6rem, 1.5vw, 0.75rem);
  display: block;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 1px;
  opacity: 0.8;
}

.stat-value {
  font-size: clamp(1rem, 3vw, 1.3rem);
  font-weight: 900;
  margin-top: 2px;
}

/* Game Container - Center */
.game-container {
  flex: 0 0 auto;
  display: flex;
  justify-content: center;
  align-items: center;
  perspective: 1000px;
}

.game-grid {
  display: grid;
  gap: var(--gap-size);
  width: min(90vw, 600px);
  height: min(90vw, 600px);
  max-width: 600px;
  max-height: 600px;
  padding: clamp(12px, 3vw, 20px);
  background: var(--primary-text);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--hover-shadow) var(--shadow-color);
}

/* Controls - Right Side on Desktop */
.controls {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap-size);
  width: 100%;
  max-width: 200px;
  min-width: 150px;
}

/* Updated Level Grids for New Difficulties */
.game-grid[data-size="12"] {
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(3, 1fr);
}

.game-grid[data-size="18"] {
  grid-template-columns: repeat(6, 1fr);
  grid-template-rows: repeat(3, 1fr);
}

.game-grid[data-size="36"] {
  grid-template-columns: repeat(6, 1fr);
  grid-template-rows: repeat(6, 1fr);
}

/* Cards */
.card {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  cursor: pointer;
  background: transparent;
}

.card.preview-mode {
  transform: rotateY(180deg);
  cursor: default;
  pointer-events: none;
}

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

.card.matched {
  transform: rotateY(180deg) scale(1.05);
  animation: matchPulse 0.8s ease-in-out;
}

.card.hint {
  animation: hintGlow 2s ease-in-out;
  box-shadow: 0 0 20px var(--hint-color),
    var(--normal-shadow) var(--shadow-color);
}

@keyframes hintGlow {
  0%,
  100% {
    box-shadow: var(--normal-shadow) var(--shadow-color);
  }
  50% {
    box-shadow: 0 0 25px var(--hint-color),
      var(--normal-shadow) var(--shadow-color);
  }
}

@keyframes matchPulse {
  0% {
    transform: rotateY(180deg) scale(1);
  }
  50% {
    transform: rotateY(180deg) scale(1.15);
  }
  100% {
    transform: rotateY(180deg) scale(1.05);
  }
}

.card.wrong {
  animation: wrongShake 0.8s ease-in-out;
}

@keyframes wrongShake {
  0%,
  100% {
    transform: rotateY(0deg);
  }
  25% {
    transform: rotateY(-15deg) translateX(-3px);
  }
  75% {
    transform: rotateY(15deg) translateX(3px);
  }
}

.card-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  border: var(--border-width) solid var(--border-color);
  font-size: clamp(1rem, 4vw, 2rem);
  font-weight: 900;
}

.card-back {
  background: var(--card-back-bg);
  color: var(--primary-bg);
  box-shadow: var(--normal-shadow) var(--shadow-color);
}

.card-back::before {
  content: "?";
  font-size: clamp(1.2rem, 5vw, 2.2rem);
  text-shadow: 1px 1px 0 var(--shadow-color);
}

.card-front {
  background: var(--card-front-bg);
  color: var(--primary-text);
  transform: rotateY(180deg);
  box-shadow: var(--normal-shadow) var(--shadow-color);
}

.btn {
  background: var(--primary-bg);
  color: var(--primary-text);
  border: var(--border-width) solid var(--border-color);
  padding: clamp(10px, 2.5vw, 14px) clamp(16px, 3vw, 24px);
  font-size: clamp(0.75rem, 2vw, 0.9rem);
  font-weight: 900;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 1px;
  transition: all 0.2s;
  box-shadow: var(--normal-shadow) var(--shadow-color);
  text-align: center;
  width: 100%;
}

.btn:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--hover-shadow) var(--shadow-color);
}

.btn:active {
  transform: translate(1px, 1px);
  box-shadow: 2px 2px 0 var(--shadow-color);
}

.btn.secondary {
  background: var(--accent-bg);
  color: var(--primary-bg);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.btn:disabled:hover {
  transform: none;
  box-shadow: var(--normal-shadow) var(--shadow-color);
}

/* Hint Button Special Styling */
.hint-btn {
  position: relative;
}

.hint-btn::after {
  content: attr(data-hints);
  position: absolute;
  top: -8px;
  right: -8px;
  background: var(--hint-color);
  color: var(--primary-bg);
  border: 2px solid var(--border-color);
  border-radius: 50%;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 900;
}
/* Universal Home Button Styling */
.home-button {
  position: fixed;
  top: 84px;
  left: 20px;
  background: #ffffff;
  color: #000000;
  text-decoration: none;
  padding: 12px 18px;
  border: 4px solid #000000;
  box-shadow: 6px 6px 0 #808080;
  font-family: "Arial Black", Arial, sans-serif;
  font-size: 0.9rem;
  font-weight: bold;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  z-index: 1000;
  transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  cursor: pointer;
  user-select: none;
}

.home-button:hover {
  background: #000000;
  color: #ffffff;
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0 #808080;
}

.home-button:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 #808080;
}

/* Mobile Layout - Stack Everything */
@media (max-width: 768px) {
  .game-layout {
    flex-direction: column;
    align-items: center;
    gap: clamp(15px, 3vh, 25px);
  }

  .stats {
    max-width: 600px;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
    order: 1;
  }

  .game-container {
    order: 2;
  }

  .controls {
    max-width: 600px;
    grid-template-columns: repeat(2, 1fr); /* Changed to 2x2 layout */
    order: 3;
  }

  .game-grid[data-size="12"] {
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(4, 1fr);
  }

  .game-grid[data-size="18"] {
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(6, 1fr);
  }

  .game-grid[data-size="36"] {
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(9, 1fr);
  }
}

@media (max-width: 480px) {
  :root {
    --card-size: min(15vw, 70px);
    --gap-size: clamp(6px, 1.5vw, 10px);
  }

  .stats {
    grid-template-columns: 1fr 1fr;
    gap: 8px;
  }

  .nav-content {
    flex-direction: column;
    text-align: center;
    gap: 8px;
  }

  .controls {
    grid-template-columns: repeat(2, 1fr); /* Keep 2x2 layout on small mobile */
    gap: 8px;
  }

  .game-grid[data-size="36"] {
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(12, 1fr);
  }
}

/* Desktop Layout Optimizations */
@media (min-width: 769px) {
  .game-layout {
    align-items: flex-start;
    justify-content: space-between;
    max-width: 1200px;
  }

  .stats {
    order: 1;
    flex: 0 0 180px;
  }

  .game-container {
    order: 2;
    flex: 1;
    max-width: 650px;
  }

  .controls {
    order: 3;
    flex: 0 0 180px;
  }

  .game-grid[data-size="18"] {
    grid-template-columns: repeat(6, 1fr);
    grid-template-rows: repeat(3, 1fr);
  }

  .game-grid[data-size="36"] {
    grid-template-columns: repeat(6, 1fr);
    grid-template-rows: repeat(6, 1fr);
  }
}

/* Overlays and Modals */
.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.9);
  z-index: 2000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: clamp(15px, 3vw, 25px);
}

.overlay-content {
  background: var(--primary-bg);
  border: var(--border-width) solid var(--border-color);
  padding: clamp(20px, 4vw, 35px);
  text-align: center;
  box-shadow: var(--hover-shadow) var(--shadow-color);
  max-width: min(90vw, 450px);
  width: 100%;
  color: var(--primary-text);
}

.overlay-content h2,
.overlay-content h3 {
  font-size: clamp(1.2rem, 4vw, 1.8rem);
  color: var(--primary-text);
  margin-bottom: clamp(12px, 2vh, 18px);
  font-weight: 900;
  text-transform: uppercase;
}

.overlay-content p {
  font-size: clamp(0.8rem, 2.5vw, 1rem);
  color: var(--secondary-text);
  margin-bottom: clamp(12px, 2vh, 18px);
  font-weight: 700;
  line-height: 1.4;
}

/* Level Selector - 3 Optimized Levels */
.level-selector {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(10px, 3vw, 15px);
  margin: clamp(15px, 3vh, 20px) 0;
}

.level-btn {
  background: var(--accent-bg);
  color: var(--primary-bg);
  border: 2px solid var(--border-color);
  padding: clamp(12px, 3vw, 16px);
  cursor: pointer;
  font-weight: 900;
  transition: all 0.2s;
  font-size: clamp(0.7rem, 1.8vw, 0.9rem);
  text-transform: uppercase;
  box-shadow: 2px 2px 0 var(--shadow-color);
  text-align: center;
  line-height: 1.3;
}

.level-btn.active {
  background: var(--primary-text);
  color: var(--primary-bg);
  transform: translate(-1px, -1px);
  box-shadow: 3px 3px 0 var(--shadow-color);
}

.level-btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: 3px 3px 0 var(--shadow-color);
}

/* Sound Controls */
.sound-controls {
  position: fixed;
  top: clamp(10px, 2vh, 15px);
  right: clamp(10px, 2vw, 15px);
  z-index: 100;
}

.sound-btn {
  background: var(--primary-bg);
  border: 2px solid var(--border-color);
  width: clamp(35px, 6vw, 45px);
  height: clamp(35px, 6vw, 45px);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(0.9rem, 2.5vw, 1.1rem);
  box-shadow: 2px 2px 0 var(--shadow-color);
  transition: all 0.2s;
}

.sound-btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: 3px 3px 0 var(--shadow-color);
}

.sound-btn.muted {
  background: var(--accent-bg);
  color: var(--primary-bg);
}

/* Modal Stats */
.modal-stats {
  background: var(--primary-text);
  color: var(--primary-bg);
  padding: clamp(12px, 3vw, 18px);
  border: 2px solid var(--shadow-color);
  margin: clamp(12px, 2vh, 18px) 0;
  box-shadow: 2px 2px 0 var(--shadow-color);
}

.modal-stats p {
  margin: clamp(4px, 1vh, 6px) 0;
  font-size: clamp(0.8rem, 2vw, 0.95rem);
  color: var(--primary-bg) !important;
  font-weight: 700;
}

.modal-stats strong {
  color: var(--primary-bg);
}

/* Settings Modal Responsive */
.settings-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  align-items: center;
  margin: 12px 0;
  text-align: left;
}

@media (max-width: 480px) {
  .settings-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 6px;
  }

  .level-selector {
    grid-template-columns: 1fr;
    gap: 8px;
  }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
  .card,
  .btn,
  .nav-btn,
  .level-btn {
    transition: none;
  }

  .card.matched,
  .card.wrong,
  .card.hint {
    animation: none;
  }
}