:root{
  --bg-gradient-start: #0a0e27;
  --bg-gradient-end: #1a1f3a;
  --glass: rgba(255,255,255,0.05);
  --glass-border: rgba(255,255,255,0.1);
  --accent: #00d4ff;
  --accent-glow: rgba(0,212,255,0.3);
  --card-back: linear-gradient(135deg, #1e293b 0%, #0f172a 100%);
  --card-front: linear-gradient(135deg, #ffffff 0%, #f1f5f9 100%);
  --gap: 6px;
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  --booster-active: #10b981;
  --booster-glow: rgba(16,185,129,0.3);
}

*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  min-height:100vh;
  font-family:var(--font-sans);
  background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
  color:#e6eef8;
  display:flex;
  align-items:stretch;
  justify-content:center;
  padding:12px;
  position:relative;
  overflow:hidden;
}
body::before{
  content:'';
  position:absolute;
  inset:0;
  background:radial-gradient(circle at 50% 0%, rgba(0,212,255,0.1), transparent 60%);
  pointer-events:none;
}

.app{
  width:100%;
  max-width:1200px;
  display:flex;
  flex-direction:column;
  gap:12px;
  height:100vh;
  position:relative;
  z-index:1;
}

.topbar{
  display:flex;
  justify-content:space-between;
  align-items:center;
  padding:12px 16px;
  background:var(--glass);
  backdrop-filter:blur(10px);
  border:1px solid var(--glass-border);
  border-radius:16px;
  box-shadow:0 8px 32px rgba(0,0,0,0.3);
  gap:12px;
}
.title{
  font-size:clamp(18px,2.5vw,26px);
  font-weight:700;
  background:linear-gradient(90deg, var(--accent), #60a5fa);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
}
.controls{
  display:flex;
  align-items:center;
  gap:8px;
}
.timer{
  font-family:monospace;
  font-size:clamp(14px,1.9vw,18px);
  padding:8px 14px;
  background:var(--glass);
  backdrop-filter:blur(10px);
  border:1px solid var(--glass-border);
  border-radius:12px;
  min-width:120px;
  text-align:center;
  font-weight:600;
  color:var(--accent);
  box-shadow:0 0 20px var(--accent-glow);
}

.booster-indicator{
  display:flex;
  align-items:center;
  gap:6px;
  padding:8px 14px;
  background:linear-gradient(135deg, var(--booster-active), #059669);
  backdrop-filter:blur(10px);
  border:1px solid var(--booster-glow);
  border-radius:12px;
  font-weight:600;
  box-shadow:0 0 20px var(--booster-glow);
  animation:boosterPulse 2s ease-in-out infinite;
}
.booster-icon{
  font-size:18px;
}
.booster-counter{
  font-family:monospace;
  font-size:16px;
  color:#fff;
  min-width:20px;
  text-align:center;
}

@keyframes boosterPulse{
  0%, 100%{box-shadow:0 0 20px var(--booster-glow)}
  50%{box-shadow:0 0 30px var(--booster-glow), 0 0 40px var(--booster-glow)}
}

.btn{
  background:var(--glass);
  backdrop-filter:blur(10px);
  border:1px solid var(--glass-border);
  color:inherit;
  padding:8px 14px;
  border-radius:12px;
  cursor:pointer;
  font-weight:600;
  font-size:14px;
  transition:all 0.3s cubic-bezier(0.4,0,0.2,1);
  box-shadow:0 4px 12px rgba(0,0,0,0.2);
}
.btn:hover{
  background:rgba(255,255,255,0.08);
  transform:translateY(-2px);
  box-shadow:0 6px 20px rgba(0,0,0,0.3);
}
.btn.primary{
  background:linear-gradient(135deg, var(--accent), #0ea5e9);
  color:#0a0e27;
  border:none;
  box-shadow:0 8px 24px var(--accent-glow);
}
.btn.primary:hover{
  box-shadow:0 12px 32px var(--accent-glow);
  transform:translateY(-3px);
}
.btn:active{transform:translateY(0)}

.game-area{
  display:flex;
  align-items:center;
  justify-content:center;
  flex:1 1 auto;
}

.board-wrap{
  width:min(95vw, 95vh);
  max-width:95vw;
  max-height:calc(100% - 160px);
  aspect-ratio:1/1;
  display:flex;
  align-items:center;
  justify-content:center;
  margin:0 auto;
}

.board{
  width:100%;
  height:100%;
  display:grid;
  gap:var(--gap);
  padding:var(--gap);
  background:var(--glass);
  backdrop-filter:blur(10px);
  border:1px solid var(--glass-border);
  border-radius:16px;
  box-shadow:0 12px 40px rgba(0,0,0,0.4), inset 0 1px 0 rgba(255,255,255,0.1);
}

.board.size-4{
  grid-template-columns:repeat(4, 1fr);
  grid-template-rows:repeat(4, 1fr);
}
.board.size-6{
  grid-template-columns:repeat(6, 1fr);
  grid-template-rows:repeat(6, 1fr);
}
.board.size-8{
  grid-template-columns:repeat(8, 1fr);
  grid-template-rows:repeat(8, 1fr);
}

.card{
  position:relative;
  width:100%;
  height:100%;
  perspective:1000px;
  cursor:pointer;
  user-select:none;
  border:none;
  background:transparent;
  padding:0;
}
.card.disabled{
  cursor:default;
  pointer-events:none;
}
.card-inner{
  position:absolute;
  inset:0;
  transform-style:preserve-3d;
  transition:transform 0.5s cubic-bezier(0.4,0,0.2,1);
  border-radius:10px;
}
.card.flipped .card-inner{
  transform:rotateY(180deg);
}
.card-face{
  position:absolute;
  inset:0;
  display:flex;
  align-items:center;
  justify-content:center;
  backface-visibility:hidden;
  border-radius:10px;
  font-size:clamp(18px, 3.4vw, 28px);
}

.card-front{
  transform:rotateY(180deg);
  background:var(--card-front);
  color:#0f172a;
  font-size:calc(min(3.6vmin, 32px));
  box-shadow:0 4px 12px rgba(0,0,0,0.2);
  border:2px solid rgba(255,255,255,0.8);
}

.card-back{
  background:var(--card-back);
  color:#64748b;
  display:flex;
  align-items:center;
  justify-content:center;
  border:1px solid var(--glass-border);
  font-size:calc(min(3.2vmin, 20px));
  font-weight:700;
  box-shadow:0 4px 12px rgba(0,0,0,0.3);
  transition:all 0.3s ease;
}
.card:not(.flipped):not(.matched):hover .card-back{
  background:linear-gradient(135deg, #2d3b52 0%, #1a2332 100%);
  border-color:var(--accent);
  box-shadow:0 0 20px var(--accent-glow);
}

.overlay{
  position:fixed;
  inset:0;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  gap:16px;
  background:linear-gradient(135deg, rgba(10,14,39,0.95), rgba(26,31,58,0.95));
  backdrop-filter:blur(20px);
  z-index:50;
  padding:24px;
  text-align:center;
  opacity:0;
  transform:scale(0.95);
  transition:opacity 0.3s, transform 0.3s;
  pointer-events:none;
}
.overlay.visible{
  opacity:1;
  transform:scale(1);
  pointer-events:auto;
}
.overlay h1, .overlay h2{
  margin-bottom:8px;
  font-size:clamp(24px,5vw,42px);
  background:linear-gradient(90deg, var(--accent), #60a5fa);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
  text-shadow:0 0 40px var(--accent-glow);
}
.overlay p{
  color:rgba(230,238,248,0.9);
  font-size:clamp(14px,2.2vw,18px);
}
.overlay .overlay-actions{display:flex;gap:12px;flex-wrap:wrap;justify-content:center}

.size-options{
  display:flex;
  flex-direction:column;
  gap:16px;
  margin-top:24px;
}

.btn-size{
  background:var(--glass);
  backdrop-filter:blur(10px);
  border:2px solid var(--glass-border);
  color:#e6eef8;
  padding:20px 32px;
  border-radius:16px;
  cursor:pointer;
  font-weight:600;
  font-size:16px;
  transition:all 0.3s cubic-bezier(0.4,0,0.2,1);
  box-shadow:0 4px 12px rgba(0,0,0,0.2);
  display:flex;
  flex-direction:column;
  gap:8px;
  min-width:240px;
}

.btn-size:hover{
  background:rgba(255,255,255,0.1);
  border-color:var(--accent);
  transform:translateY(-4px);
  box-shadow:0 8px 24px var(--accent-glow);
}

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

.size-label{
  font-size:28px;
  font-weight:700;
  background:linear-gradient(90deg, var(--accent), #60a5fa);
  -webkit-background-clip:text;
  -webkit-text-fill-color:transparent;
  background-clip:text;
}

.size-desc{
  font-size:14px;
  color:rgba(230,238,248,0.7);
  font-weight:500;
}

.booster-desc{
  font-size:clamp(16px,2.5vw,20px);
  margin-bottom:8px;
}

.booster-info{
  font-size:clamp(14px,2vw,16px);
  color:rgba(230,238,248,0.7);
}

.best-time{
  font-size:clamp(16px,2.5vw,20px);
  font-weight:600;
  color:#fbbf24;
  margin-top:8px;
}

.new-record{
  font-size:clamp(15px,2.3vw,19px);
  font-weight:700;
  color:#10b981;
  margin-top:4px;
  animation:recordPulse 1s ease-in-out infinite;
}

@keyframes recordPulse{
  0%, 100%{opacity:1;transform:scale(1)}
  50%{opacity:0.8;transform:scale(1.05)}
}

.paused .board{
  filter:blur(4px) brightness(0.7);
  pointer-events:none;
  user-select:none;
}
.paused .topbar .btn#btnPause{
  background:linear-gradient(135deg, #fbbf24, #f59e0b);
  color:#0a0e27;
}

.card.matched .card-front{
  box-shadow:0 0 30px var(--accent-glow), 0 4px 12px rgba(0,0,0,0.2);
  border-color:var(--accent);
  animation:matchPulse 0.5s ease-out;
}

@keyframes matchPulse{
  0%{transform:scale(1)}
  50%{transform:scale(1.05)}
  100%{transform:scale(1)}
}

@media (max-width:420px){
  .controls{gap:6px}
  .timer{min-width:100px;font-size:13px;padding:6px 10px}
  .btn{padding:6px 10px;font-size:13px}
  .topbar{padding:10px 12px}
  .size-options{gap:12px}
  .btn-size{padding:16px 24px;min-width:200px}
  .booster-indicator{padding:6px 10px;gap:4px}
  .booster-icon{font-size:16px}
  .booster-counter{font-size:14px}
}