/* ============================================
   Memory Card Game - Stylesheet
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
  /* Light theme */
  --bg-primary: #f0f2f5;
  --bg-secondary: #ffffff;
  --bg-card: #4a90d9;
  --bg-card-face: #ffffff;
  --text-primary: #1a1a2e;
  --text-secondary: #555;
  --text-muted: #888;
  --border-color: #ddd;
  --shadow-color: rgba(0, 0, 0, 0.1);
  --shadow-hover: rgba(0, 0, 0, 0.2);
  --accent: #4a90d9;
  --accent-hover: #357abd;
  --success: #2ecc71;
  --match-glow: rgba(46, 204, 113, 0.5);
  --mismatch-glow: rgba(231, 76, 60, 0.5);
  --card-radius: 12px;
  --transition-speed: 0.15s;
  --flip-speed: 0.5s;
}

[data-theme="dark"] {
  --bg-primary: #0f0f1a;
  --bg-secondary: #1a1a2e;
  --bg-card: #2d5a8e;
  --bg-card-face: #16213e;
  --text-primary: #e0e0e0;
  --text-secondary: #aaa;
  --text-muted: #666;
  --border-color: #333;
  --shadow-color: rgba(0, 0, 0, 0.3);
  --shadow-hover: rgba(74, 144, 217, 0.3);
  --accent: #5dade2;
  --accent-hover: #3498db;
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  transition: background-color var(--transition-speed), color var(--transition-speed);
}

.app {
  max-width: 800px;
  margin: 0 auto;
  padding: 1rem;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* --- Header --- */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0 1rem;
}

.header__title {
  font-size: 1.8rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent), #e74c3c);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* --- Buttons --- */
.btn {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  font-family: inherit;
  font-size: 1rem;
  transition: transform var(--transition-speed), box-shadow var(--transition-speed),
    background-color var(--transition-speed);
}

.btn:hover {
  transform: translateY(-2px);
}

.btn:active {
  transform: translateY(0);
}

.btn--icon {
  background: var(--bg-secondary);
  padding: 0.5rem 0.75rem;
  font-size: 1.3rem;
  box-shadow: 0 2px 8px var(--shadow-color);
}

.btn--difficulty {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.3rem;
  background: var(--bg-secondary);
  padding: 1.5rem 2rem;
  box-shadow: 0 4px 12px var(--shadow-color);
  border: 2px solid transparent;
  min-width: 140px;
}

.btn--difficulty:hover {
  border-color: var(--accent);
  box-shadow: 0 6px 20px var(--shadow-hover);
}

.btn__emoji {
  font-size: 2rem;
}

.btn__label {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.btn__desc {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.btn--theme {
  background: var(--bg-secondary);
  padding: 0.5rem 1rem;
  box-shadow: 0 2px 6px var(--shadow-color);
  border: 2px solid transparent;
  color: var(--text-primary);
}

.btn--theme.active {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
}

.btn--small {
  background: var(--bg-secondary);
  padding: 0.4rem 0.8rem;
  font-size: 0.85rem;
  box-shadow: 0 2px 6px var(--shadow-color);
  color: var(--text-primary);
}

.btn--primary {
  background: var(--accent);
  color: #fff;
  padding: 0.75rem 2rem;
  font-size: 1.1rem;
  font-weight: 600;
  box-shadow: 0 4px 12px var(--shadow-color);
}

.btn--primary:hover {
  background: var(--accent-hover);
}

.btn--secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  padding: 0.75rem 2rem;
  font-size: 1.1rem;
  box-shadow: 0 4px 12px var(--shadow-color);
}

.btn--sound {
  position: fixed;
  bottom: 1rem;
  right: 1rem;
  background: var(--bg-secondary);
  padding: 0.6rem 0.8rem;
  font-size: 1.3rem;
  box-shadow: 0 2px 10px var(--shadow-color);
  border-radius: 50%;
  z-index: 100;
}

/* --- Screens --- */
.screen {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.hidden {
  display: none !important;
}

/* --- Menu Screen --- */
.screen--menu {
  justify-content: center;
  align-items: center;
}

.menu {
  text-align: center;
}

.menu__heading {
  font-size: 1.4rem;
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
}

.menu__options {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

.menu__theme-select {
  margin-bottom: 2rem;
}

.menu__theme-select h3 {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

.menu__themes {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  flex-wrap: wrap;
}

.menu__best-scores {
  margin-top: 1rem;
  padding: 1rem;
  background: var(--bg-secondary);
  border-radius: 12px;
  box-shadow: 0 2px 8px var(--shadow-color);
  text-align: left;
  display: none;
}

.menu__best-scores.visible {
  display: block;
}

.menu__best-scores h3 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
  text-align: center;
}

.menu__best-scores .score-row {
  display: flex;
  justify-content: space-between;
  padding: 0.35rem 0;
  font-size: 0.9rem;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-color);
}

.menu__best-scores .score-row:last-child {
  border-bottom: none;
}

.score-row__label {
  font-weight: 600;
  text-transform: capitalize;
}

/* --- Stats Bar --- */
.stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding: 0.75rem 1rem;
  background: var(--bg-secondary);
  border-radius: 12px;
  box-shadow: 0 2px 8px var(--shadow-color);
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.stats__item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
}

.stats__label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.stats__value {
  font-size: 1.1rem;
  font-weight: 700;
}

.stats__actions {
  display: flex;
  gap: 0.5rem;
}

/* --- Card Grid --- */
.card-grid {
  display: grid;
  gap: 0.6rem;
  justify-content: center;
  perspective: 1000px;
  flex: 1;
  align-content: start;
  padding: 0.5rem 0;
}

.card-grid[data-cols="4"] {
  grid-template-columns: repeat(4, 1fr);
  max-width: 440px;
  margin: 0 auto;
  width: 100%;
}

.card-grid[data-cols="5"] {
  grid-template-columns: repeat(5, 1fr);
  max-width: 500px;
  margin: 0 auto;
  width: 100%;
}

.card-grid[data-cols="6"] {
  grid-template-columns: repeat(6, 1fr);
  max-width: 560px;
  margin: 0 auto;
  width: 100%;
}

/* --- Card --- */
.card {
  aspect-ratio: 1;
  cursor: pointer;
  position: relative;
  transform-style: preserve-3d;
  transition: transform var(--flip-speed) ease;
}

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

.card.matched {
  transform: rotateY(180deg);
  cursor: default;
}

.card__face {
  position: absolute;
  inset: 0;
  border-radius: var(--card-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transition: box-shadow 0.3s;
}

.card__face--back {
  background: linear-gradient(135deg, var(--bg-card), color-mix(in srgb, var(--bg-card), #000 20%));
  box-shadow: 0 3px 10px var(--shadow-color);
  font-size: 1.8rem;
  color: rgba(255, 255, 255, 0.3);
}

.card__face--back::after {
  content: '?';
  font-weight: bold;
}

.card__face--front {
  background: var(--bg-card-face);
  transform: rotateY(180deg);
  box-shadow: 0 3px 10px var(--shadow-color);
  font-size: 2rem;
}

.card:hover:not(.flipped):not(.matched) {
  transform: translateY(-3px);
}

.card:hover:not(.flipped):not(.matched) .card__face--back {
  box-shadow: 0 6px 16px var(--shadow-hover);
}

/* Match/mismatch animations */
.card.match-anim .card__face--front {
  box-shadow: 0 0 20px var(--match-glow);
  animation: matchPulse 0.5s ease;
}

.card.mismatch-anim .card__face--front {
  box-shadow: 0 0 20px var(--mismatch-glow);
  animation: shake 0.4s ease;
}

@keyframes matchPulse {
  0%, 100% { transform: rotateY(180deg) scale(1); }
  50% { transform: rotateY(180deg) scale(1.08); }
}

@keyframes shake {
  0%, 100% { transform: rotateY(180deg) translateX(0); }
  25% { transform: rotateY(180deg) translateX(-5px); }
  75% { transform: rotateY(180deg) translateX(5px); }
}

.card.matched .card__face--front {
  box-shadow: 0 0 12px var(--match-glow);
}

/* --- Win Screen --- */
.screen--win {
  justify-content: center;
  align-items: center;
}

.win {
  text-align: center;
  background: var(--bg-secondary);
  padding: 2.5rem;
  border-radius: 16px;
  box-shadow: 0 8px 30px var(--shadow-color);
  max-width: 400px;
  width: 100%;
  animation: fadeInUp 0.5s ease;
}

.win__title {
  font-size: 2rem;
  margin-bottom: 1.5rem;
}

.win__stats {
  margin-bottom: 1.5rem;
}

.win__stats p {
  font-size: 1.1rem;
  margin: 0.5rem 0;
  color: var(--text-secondary);
}

.win__record {
  background: linear-gradient(135deg, #f1c40f, #f39c12);
  color: #1a1a2e;
  padding: 0.75rem;
  border-radius: 8px;
  font-weight: 700;
  margin-bottom: 1.5rem;
  animation: fadeInUp 0.5s ease 0.3s both;
}

.win__actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* --- Responsive --- */
@media (max-width: 600px) {
  .app {
    padding: 0.5rem;
  }

  .header__title {
    font-size: 1.3rem;
  }

  .menu__options {
    flex-direction: column;
    align-items: center;
  }

  .btn--difficulty {
    width: 100%;
    max-width: 280px;
    padding: 1rem;
  }

  .stats {
    gap: 0.75rem;
    padding: 0.5rem;
    font-size: 0.9rem;
  }

  .card-grid {
    gap: 0.4rem;
  }

  .card__face--front {
    font-size: 1.5rem;
  }

  .card__face--back {
    font-size: 1.3rem;
  }

  .card-grid[data-cols="6"] {
    gap: 0.3rem;
  }

  .win {
    padding: 1.5rem;
    margin: 0 0.5rem;
  }
}

@media (max-width: 400px) {
  .card__face--front {
    font-size: 1.2rem;
  }

  .stats {
    gap: 0.5rem;
  }

  .stats__value {
    font-size: 0.95rem;
  }
}