:root {
  --bg-primary: #0D1117;
  --bg-secondary: #161B22;
  --bg-tertiary: #21262D;
  --text-primary: #F0F6FC;
  --text-secondary: #8B949E;
  --text-muted: #484F58;
  --accent: #3B82F6;
  --border: #30363D;
  --btn-bg: #21262D;
  --btn-active: #30363D;
  --overlay-bg: rgba(0, 0, 0, 0.85);
  --board-bg: #0A0E14;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg-primary: #FFFFFF;
    --bg-secondary: #F6F8FA;
    --bg-tertiary: #E9ECF0;
    --text-primary: #1B1E28;
    --text-secondary: #57606A;
    --text-muted: #8C959F;
    --accent: #3182F6;
    --border: #D0D7DE;
    --btn-bg: #E9ECF0;
    --btn-active: #D0D7DE;
    --overlay-bg: rgba(255, 255, 255, 0.9);
    --board-bg: #F0F2F5;
  }
}

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

html, body {
  height: 100%;
  width: 100%;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, 'Pretendard', 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  touch-action: none;
  user-select: none;
}

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100dvh;
}

#app {
  position: relative;
  width: 100%;
  max-width: 480px;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  background: var(--bg-secondary);
  overflow: hidden;
}

/* Header */
#header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  gap: 8px;
}

.header-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.header-label {
  font-size: 10px;
  color: var(--text-muted);
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.header-value {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
}

.lives-display {
  display: flex;
  gap: 4px;
  align-items: center;
}

.life-icon {
  font-size: 16px;
  filter: drop-shadow(0 0 4px rgba(59, 130, 246, 0.6));
}

.life-icon.lost {
  opacity: 0.2;
  filter: none;
}

/* Canvas Area */
#canvas-wrapper {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--board-bg);
  position: relative;
  overflow: hidden;
}

#gameCanvas {
  display: block;
  image-rendering: pixelated;
}

/* Controls */
#controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: var(--bg-primary);
  border-top: 1px solid var(--border);
  flex-shrink: 0;
  gap: 12px;
}

.ctrl-group {
  display: flex;
  gap: 8px;
}

.ctrl-btn {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--btn-bg);
  color: var(--text-primary);
  font-size: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.1s, transform 0.1s, box-shadow 0.1s;
  -webkit-tap-highlight-color: transparent;
  flex-shrink: 0;
}

.ctrl-btn:active,
.ctrl-btn.pressed {
  background: var(--btn-active);
  transform: scale(0.93);
  box-shadow: 0 0 0 2px var(--accent);
}

#fireBtn {
  width: 68px;
  height: 68px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
  font-size: 24px;
  box-shadow: 0 0 16px rgba(59, 130, 246, 0.5);
  transition: background 0.1s, transform 0.1s, box-shadow 0.1s;
}

#fireBtn:active,
#fireBtn.pressed {
  background: #2563eb;
  transform: scale(0.93);
  box-shadow: 0 0 24px rgba(59, 130, 246, 0.8);
}

/* Overlay Screens */
.overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--overlay-bg);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 10;
  padding: 32px 24px;
  text-align: center;
  gap: 24px;
  transition: opacity 0.3s;
}

.overlay.hidden {
  display: none;
}

.overlay-title {
  font-size: 48px;
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 1;
  background: linear-gradient(135deg, #3B82F6, #8B5CF6, #EC4899);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.overlay-subtitle {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 280px;
}

.overlay-score-box {
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 32px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 180px;
}

.overlay-score-label {
  font-size: 11px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
}

.overlay-score-value {
  font-size: 36px;
  font-weight: 800;
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.03em;
}

.high-score-row {
  display: flex;
  flex-direction: column;
  gap: 4px;
  align-items: center;
}

.high-score-label {
  font-size: 11px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.high-score-value {
  font-size: 22px;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.overlay-btn {
  padding: 14px 40px;
  border-radius: 12px;
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 16px;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  letter-spacing: -0.01em;
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.4);
  transition: transform 0.1s, box-shadow 0.1s;
  -webkit-tap-highlight-color: transparent;
}

.overlay-btn:active {
  transform: scale(0.96);
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.4);
}

.alien-legend {
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: flex-start;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 20px;
}

.alien-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.alien-row span:first-child {
  font-size: 20px;
  width: 28px;
  text-align: center;
}

.alien-row span:last-child {
  font-size: 13px;
  color: var(--text-secondary);
  font-weight: 500;
}

/* Level / Status Badge */
#level-badge {
  font-size: 11px;
  color: var(--text-muted);
  padding: 2px 8px;
  border: 1px solid var(--border);
  border-radius: 20px;
  white-space: nowrap;
}

/* Responsive tweaks for very short screens */
@media (max-height: 600px) {
  #header {
    padding: 6px 12px;
  }
  .header-value {
    font-size: 15px;
  }
  #controls {
    padding: 8px 12px;
  }
  .ctrl-btn {
    width: 44px;
    height: 44px;
    font-size: 18px;
  }
  #fireBtn {
    width: 56px;
    height: 56px;
  }
}