: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%;
  overflow: hidden;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Pretendard', 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100dvh;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

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

/* HUD */
#hud {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 16px 20px 12px;
  pointer-events: none;
}

.hud-box {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.hud-box.right {
  align-items: flex-end;
}

.hud-label {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.hud-value {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.hud-value.best {
  font-size: 20px;
  color: var(--text-secondary);
}

/* Canvas */
#game-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: block;
  background: var(--board-bg);
  cursor: pointer;
}

/* Overlays */
.overlay {
  position: absolute;
  inset: 0;
  z-index: 20;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--overlay-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  gap: 0;
  transition: opacity 0.3s ease;
}

.overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.overlay-title {
  font-size: clamp(52px, 16vw, 80px);
  font-weight: 900;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, var(--accent) 0%, #a78bfa 50%, #f472b6 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 8px;
  line-height: 1;
}

.overlay-subtitle {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 48px;
  letter-spacing: 0.01em;
}

.overlay-score-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  margin-bottom: 40px;
}

.overlay-score-label {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.overlay-score-value {
  font-size: 64px;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.overlay-best {
  font-size: 14px;
  color: var(--text-secondary);
  margin-top: -4px;
}

.overlay-best span {
  color: var(--accent);
  font-weight: 600;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 48px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--btn-bg);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease, border-color 0.15s ease;
  letter-spacing: 0.01em;
  touch-action: manipulation;
}

.btn:hover {
  background: var(--btn-active);
  border-color: var(--accent);
}

.btn:active {
  transform: scale(0.97);
}

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

.btn.primary:hover {
  background: #2563eb;
  border-color: #2563eb;
}

.hint-text {
  margin-top: 20px;
  font-size: 12px;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

/* Perfect feedback */
#perfect-text {
  position: absolute;
  top: 35%;
  left: 50%;
  transform: translateX(-50%);
  z-index: 15;
  font-size: 28px;
  font-weight: 800;
  letter-spacing: 0.05em;
  color: #fff;
  text-shadow: 0 0 20px rgba(59, 130, 246, 0.8), 0 2px 8px rgba(0,0,0,0.5);
  pointer-events: none;
  opacity: 0;
  transition: none;
  white-space: nowrap;
}

#perfect-text.show {
  animation: perfectPop 0.9s ease-out forwards;
}

@keyframes perfectPop {
  0%   { opacity: 0; transform: translateX(-50%) scale(0.6) translateY(10px); }
  20%  { opacity: 1; transform: translateX(-50%) scale(1.15) translateY(-4px); }
  40%  { transform: translateX(-50%) scale(1) translateY(0px); }
  70%  { opacity: 1; transform: translateX(-50%) scale(1) translateY(-6px); }
  100% { opacity: 0; transform: translateX(-50%) scale(0.9) translateY(-20px); }
}

/* Score pop */
.score-pop {
  position: absolute;
  z-index: 14;
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
  pointer-events: none;
  animation: scoreFly 0.8s ease-out forwards;
}

@keyframes scoreFly {
  0%   { opacity: 1; transform: translateY(0) scale(1); }
  100% { opacity: 0; transform: translateY(-50px) scale(0.8); }
}

/* Responsive tweaks */
@media (max-height: 600px) {
  .hud-value { font-size: 22px; }
  .hud-value.best { font-size: 16px; }
  .overlay-score-value { font-size: 48px; }
  .overlay-title { font-size: 48px; }
}