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

:root {
  --neon-blue: #00e0ff;
  --dark-bg: #0c0c0c;
  --panel-bg: #1a1a1a;
  --text-primary: #ffffff;
  --text-secondary: #cccccc;
  --text-muted: #888888;
  --accent-green: #00ff88;
  --accent-red: #ff3366;
}

body {
  font-family: 'Segoe UI', 'Roboto', 'Helvetica Neue', sans-serif;
  background: var(--dark-bg);
  color: var(--text-primary);
  overflow: hidden;
  touch-action: none;
  -webkit-user-select: none;
  user-select: none;
}

/* Screen Management */
.screen {
  display: none;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
}

.screen.active {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

/* HUD Header */
.hud-header {
  text-align: center;
  margin-bottom: 40px;
}

.hud-header h1 {
  font-size: clamp(1.5rem, 5vw, 2.5rem);
  color: var(--neon-blue);
  letter-spacing: 4px;
  font-weight: 700;
  text-shadow: 0 0 20px rgba(0, 224, 255, 0.6);
}

.hud-header h2 {
  font-size: clamp(1rem, 3vw, 1.5rem);
  color: var(--text-secondary);
  letter-spacing: 2px;
  font-weight: 300;
  margin-top: 10px;
}

/* Menu Screen */
.menu-content {
  max-width: 600px;
  width: 90%;
  padding: 20px;
}

.mission-brief {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1rem;
  line-height: 1.6;
  margin-bottom: 30px;
}

.stats-panel {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 15px;
  margin-bottom: 30px;
  padding: 20px;
  background: var(--panel-bg);
  border: 1px solid rgba(0, 224, 255, 0.2);
  border-radius: 8px;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 1px;
}

.stat-value {
  font-size: 1.5rem;
  color: var(--neon-blue);
  font-weight: 700;
}

/* Tier Selection */
.tier-select {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 30px;
}

.tier-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 20px;
  background: var(--panel-bg);
  border: 2px solid var(--neon-blue);
  border-radius: 8px;
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.tier-btn:hover:not(.locked) {
  background: rgba(0, 224, 255, 0.1);
  box-shadow: 0 0 20px rgba(0, 224, 255, 0.4);
  transform: translateY(-2px);
}

.tier-btn.selected {
  border-color: var(--accent-green);
  box-shadow: 0 0 20px rgba(0, 255, 136, 0.4);
}

.tier-btn.locked {
  border-color: #333;
  opacity: 0.5;
  cursor: not-allowed;
}

.tier-name {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--neon-blue);
  letter-spacing: 2px;
}

.tier-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 5px;
}

.unlock-req {
  font-size: 0.75rem;
  color: var(--accent-red);
  margin-top: 8px;
}

/* Buttons */
.primary-btn, .secondary-btn {
  padding: 16px 40px;
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: 2px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-transform: uppercase;
  width: 100%;
  max-width: 400px;
}

.primary-btn {
  background: var(--neon-blue);
  color: var(--dark-bg);
  box-shadow: 0 0 20px rgba(0, 224, 255, 0.5);
}

.primary-btn:hover {
  background: #00b8cc;
  box-shadow: 0 0 30px rgba(0, 224, 255, 0.8);
  transform: translateY(-2px);
}

.secondary-btn {
  background: transparent;
  color: var(--neon-blue);
  border: 2px solid var(--neon-blue);
}

.secondary-btn:hover {
  background: rgba(0, 224, 255, 0.1);
  box-shadow: 0 0 15px rgba(0, 224, 255, 0.3);
}

/* Game Screen */
#gameScreen {
  background: var(--dark-bg);
}

.game-hud {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  display: flex;
  justify-content: space-between;
  padding: 15px 20px;
  background: linear-gradient(to bottom, rgba(12, 12, 12, 0.95), transparent);
  z-index: 10;
}

.hud-left, .hud-center, .hud-right {
  display: flex;
  gap: 20px;
}

.hud-item {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hud-item.large .hud-value {
  font-size: 2rem;
}

.hud-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 1px;
  margin-bottom: 4px;
}

.hud-value {
  font-size: 1.2rem;
  color: var(--neon-blue);
  font-weight: 700;
}

#gameCanvas {
  width: 100%;
  height: 100vh;
  display: block;
  background: linear-gradient(to bottom, #0a3a2a, #051510);
}

.tap-indicator {
  position: absolute;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%);
  padding: 12px 30px;
  background: rgba(0, 224, 255, 0.2);
  border: 2px solid var(--neon-blue);
  border-radius: 25px;
  color: var(--neon-blue);
  font-size: 1rem;
  letter-spacing: 2px;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.6; }
  50% { opacity: 1; }
}

/* Results Screen */
.results-content {
  max-width: 600px;
  width: 90%;
  padding: 20px;
}

.results-panel {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-bottom: 30px;
  padding: 30px;
  background: var(--panel-bg);
  border: 1px solid rgba(0, 224, 255, 0.2);
  border-radius: 8px;
}

.result-stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.result-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  letter-spacing: 1px;
}

.result-value {
  font-size: 2rem;
  color: var(--neon-blue);
  font-weight: 700;
}

.new-unlock {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
  padding: 20px;
  margin-bottom: 30px;
  background: rgba(0, 255, 136, 0.1);
  border: 2px solid var(--accent-green);
  border-radius: 8px;
  animation: unlockPulse 1.5s infinite;
}

.new-unlock.hidden {
  display: none;
}

.unlock-icon {
  font-size: 2rem;
}

.unlock-text {
  font-size: 1.2rem;
  color: var(--accent-green);
  font-weight: 700;
  letter-spacing: 2px;
}

@keyframes unlockPulse {
  0%, 100% { box-shadow: 0 0 20px rgba(0, 255, 136, 0.3); }
  50% { box-shadow: 0 0 40px rgba(0, 255, 136, 0.6); }
}

.results-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: center;
}

/* Mobile Optimization */
@media (max-width: 768px) {
  .stats-panel {
    grid-template-columns: 1fr;
    gap: 10px;
    padding: 15px;
  }
  
  .results-panel {
    grid-template-columns: 1fr;
    gap: 15px;
    padding: 20px;
  }
  
  .game-hud {
    padding: 10px;
  }
  
  .hud-left, .hud-center, .hud-right {
    gap: 10px;
  }
  
  .hud-item {
    font-size: 0.85rem;
  }
}