:root {
  --color-primary: #6b6b6b;
  --color-bg: #1a1a1a;
  --color-surface: #2a2a2a;
  --color-border: #3a3a3a;
  --color-text: #e0e0e0;
  --color-danger: #ff00ff;
  --color-neon-cyan: #00ffff;
  --color-neon-pink: #ff00aa;
  --color-neon-green: #00ff66;
  --color-neon-yellow: #ffff00;
  --space-fibonacci-5: 13px;
  --snap-duration: 150ms;
  --snap-easing: cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: 'Courier New', monospace;
  user-select: none;
}

#game-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
  padding: var(--space-fibonacci-5);
  gap: var(--space-fibonacci-5);
}

#hud {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  max-width: 720px;
  padding: 0 var(--space-fibonacci-5);
  font-size: 14px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

#hud-left, #hud-right {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

#hud-right {
  text-align: right;
}

.label {
  font-size: 10px;
  color: var(--color-primary);
  letter-spacing: 0.15em;
}

.value {
  font-size: 18px;
  font-weight: bold;
  color: var(--color-text);
}

#meter-container {
  width: 100%;
  max-width: 720px;
  height: 20px;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  position: relative;
  overflow: hidden;
}

#vibes-overflow {
  height: 100%;
  width: 0%;
  background: var(--color-neon-cyan);
  transition: width var(--snap-duration) var(--snap-easing),
              background var(--snap-duration) var(--snap-easing);
  will-change: width, background;
  position: relative;
}

#vibes-overflow::after {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    90deg,
    transparent,
    transparent 4px,
    rgba(0, 0, 0, 0.3) 4px,
    rgba(0, 0, 0, 0.3) 8px
  );
}

#grid-container {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  grid-template-rows: repeat(4, 1fr);
  gap: var(--space-fibonacci-5);
  width: 100%;
  max-width: 720px;
  aspect-ratio: 3 / 2;
  padding: var(--space-fibonacci-5);
  background: var(--color-surface);
  border: 2px solid var(--color-primary);
  position: relative;
}

.grid-cell {
  background: rgba(107, 107, 107, 0.08);
  border: 1px solid var(--color-border);
  position: relative;
  overflow: hidden;
}

.entity {
  position: absolute;
  inset: 2px;
  background: var(--color-neon-cyan);
  will-change: transform;
  transition: transform var(--snap-duration) var(--snap-easing),
              opacity var(--snap-duration) var(--snap-easing);
  opacity: 0;
  transform: translate(0, 0) scale(0);
}

.entity.active {
  opacity: 1;
  transform: translate(0, 0) scale(1);
}

.entity.jittering {
  animation: none;
}

.entity.snapping {
  transition: transform var(--snap-duration) var(--snap-easing);
  transform: translate(0, 0) scale(1) !important;
}

#snap-button {
  margin-top: var(--space-fibonacci-5);
  padding: var(--space-fibonacci-5) calc(var(--space-fibonacci-5) * 2);
  background: var(--color-surface);
  border: 2px solid var(--color-primary);
  color: var(--color-text);
  font-family: inherit;
  font-size: 14px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  cursor: pointer;
  transition: border-color 100ms, background 100ms;
}

#snap-button:hover {
  border-color: var(--color-text);
  background: rgba(224, 224, 224, 0.05);
}

#snap-button:active {
  transform: scale(0.97);
}

#snap-button:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

#overlay {
  position: fixed;
  inset: 0;
  background: rgba(26, 26, 26, 0.95);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 100;
  gap: var(--space-fibonacci-5);
}

#overlay.hidden {
  display: none;
}

#overlay h1 {
  font-size: 32px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

#overlay p {
  font-size: 14px;
  color: var(--color-primary);
  max-width: 400px;
  text-align: center;
  line-height: 1.6;
}

#overlay button {
  padding: var(--space-fibonacci-5) calc(var(--space-fibonacci-5) * 3);
  background: var(--color-surface);
  border: 2px solid var(--color-primary);
  color: var(--color-text);
  font-family: inherit;
  font-size: 14px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  cursor: pointer;
}

#overlay button:hover {
  border-color: var(--color-text);
}

#flash {
  position: fixed;
  inset: 0;
  background: rgba(107, 107, 107, 0.15);
  pointer-events: none;
  opacity: 0;
  z-index: 50;
  transition: opacity var(--snap-duration) var(--snap-easing);
}

#flash.active {
  opacity: 1;
}

#game-container.shake {
  animation: shake 150ms ease-out;
}

@keyframes shake {
  0% { transform: translate(0, 0); }
  10% { transform: translate(-2px, 1px); }
  20% { transform: translate(2px, -1px); }
  30% { transform: translate(-1px, 2px); }
  40% { transform: translate(1px, -2px); }
  50% { transform: translate(-2px, 0); }
  60% { transform: translate(2px, 1px); }
  70% { transform: translate(-1px, -1px); }
  80% { transform: translate(1px, 2px); }
  90% { transform: translate(-1px, -1px); }
  100% { transform: translate(0, 0); }
}

.chaos-mode #grid-container {
  border-color: var(--color-danger);
  animation: chaosPulse 0.5s ease-in-out infinite;
}

@keyframes chaosPulse {
  0%, 100% { border-color: var(--color-danger); }
  50% { border-color: var(--color-neon-cyan); }
}

.chaos-mode #vibes-overflow {
  background: var(--color-danger) !important;
}

.chaos-mode .grid-cell {
  background: rgba(255, 0, 255, 0.1);
  border-color: rgba(255, 0, 255, 0.3);
}

#combo-display {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 48px;
  font-weight: bold;
  color: var(--color-neon-cyan);
  pointer-events: none;
  opacity: 0;
  z-index: 60;
  text-shadow: 0 0 20px var(--color-neon-cyan);
}

#combo-display.show {
  animation: comboPop 400ms ease-out forwards;
}

@keyframes comboPop {
  0% { opacity: 1; transform: translate(-50%, -50%) scale(0.5); }
  50% { opacity: 1; transform: translate(-50%, -50%) scale(1.2); }
  100% { opacity: 0; transform: translate(-50%, -60%) scale(1); }
}