/* ─── Design tokens ─── */
:root {
  --bg-deep: #0a0e17;
  --bg-panel: rgba(14, 20, 35, 0.85);
  --bg-panel-border: rgba(100, 180, 255, 0.15);
  --accent-cyan: #00e5ff;
  --accent-magenta: #ff2d95;
  --accent-purple: #9d4edd;
  --accent-gold: #ffd166;
  --text-primary: #e8f0fe;
  --text-muted: #7a8ba8;
  --glow-cyan: 0 0 20px rgba(0, 229, 255, 0.4);
  --glow-magenta: 0 0 20px rgba(255, 45, 149, 0.4);
  --font-display: 'Orbitron', sans-serif;
  --font-body: 'Rajdhani', sans-serif;
  --board-radius: 4px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-size: 16px;
  height: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  height: 100%;
  min-height: 100vh;
  font-family: var(--font-body);
  background: var(--bg-deep);
  color: var(--text-primary);
  overflow: hidden;
}

/* ─── Background effects ─── */
.app {
  position: relative;
  width: 100%;
  height: 100vh;
  max-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0.35rem 0.75rem 0.5rem;
  overflow: hidden;
}

.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(0, 229, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 229, 255, 0.03) 1px, transparent 1px);
  background-size: 40px 40px;
  animation: grid-drift 20s linear infinite;
  pointer-events: none;
  z-index: 0;
}

.bg-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
}

@keyframes grid-drift {
  0% { transform: translateY(0); }
  100% { transform: translateY(40px); }
}

.bg-glow {
  position: fixed;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.25;
  pointer-events: none;
  z-index: 0;
}

.bg-glow--left {
  top: 10%;
  left: -10%;
  background: var(--accent-purple);
  animation: glow-drift 8s ease-in-out infinite;
}

.bg-glow--right {
  bottom: 10%;
  right: -10%;
  background: var(--accent-cyan);
  animation: glow-drift 8s ease-in-out infinite reverse;
}

@keyframes glow-drift {
  0%, 100% { transform: translate(0, 0) scale(1); opacity: 0.25; }
  50% { transform: translate(30px, -20px) scale(1.1); opacity: 0.35; }
}

/* ─── Header ─── */
.header--side {
  position: relative;
  z-index: 1;
  flex-shrink: 0;
  text-align: left;
  padding-bottom: 0.65rem;
  margin-bottom: 0.15rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.header--side .logo {
  flex-direction: column;
  align-items: flex-start;
  gap: 0.15rem;
}

.header--side .logo__icon {
  font-size: 1.5rem;
}

.header--side .logo__text {
  font-size: 1.05rem;
  letter-spacing: 0.22em;
  line-height: 1.2;
}

.header--side .tagline {
  margin-top: 0.35rem;
  font-size: 0.62rem;
  letter-spacing: 0.14em;
  line-height: 1.45;
}

.header--side .help-link {
  margin-top: 0.5rem;
  font-size: 0.62rem;
  padding: 0.3rem 0.55rem;
}

.logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
}

.logo__icon {
  font-size: 2rem;
  color: var(--accent-cyan);
  text-shadow: var(--glow-cyan);
  animation: pulse-glow 3s ease-in-out infinite;
}

.logo__text {
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 3.5vw, 2.25rem);
  font-weight: 900;
  letter-spacing: 0.35em;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta), var(--accent-purple));
  background-size: 200% 200%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: title-shimmer 4s ease infinite;
}

@keyframes title-shimmer {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

.tagline {
  margin-top: 0.15rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

.help-link {
  display: inline-block;
  margin-top: 0.35rem;
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  text-decoration: none;
  padding: 0.35rem 0.85rem;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  transition: var(--transition);
}

.help-link:hover {
  color: var(--accent-cyan);
  border-color: rgba(0, 229, 255, 0.3);
  box-shadow: 0 0 12px rgba(0, 229, 255, 0.15);
}

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

/* ─── Layout ─── */
.game-layout {
  position: relative;
  z-index: 1;
  flex: 1;
  min-height: 0;
  width: 100%;
  max-width: 1200px;
  display: flex;
  align-items: stretch;
  justify-content: center;
  gap: 0.85rem;
}

/* ─── Panels ─── */
.panel {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  width: 168px;
  flex-shrink: 0;
  min-height: 0;
}

.panel--left {
  justify-content: flex-start;
}

.panel--right {
  justify-content: center;
}

.panel--left .stat-card--stats {
  flex: 1;
  min-height: 0;
}

.stat-card {
  background: var(--bg-panel);
  border: 1px solid var(--bg-panel-border);
  border-radius: 12px;
  padding: 0.75rem;
  backdrop-filter: blur(12px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.stat-card:hover {
  border-color: rgba(0, 229, 255, 0.25);
  box-shadow: 0 8px 32px rgba(0, 229, 255, 0.08);
}

.stat-card__label {
  display: block;
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--accent-cyan);
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.stat-card__hint {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
}

.mini-board {
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.4);
  border-radius: var(--board-radius);
  padding: 0.5rem;
}

.mini-board canvas {
  display: block;
  image-rendering: pixelated;
  image-rendering: crisp-edges;
}

.stat-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.4rem 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.stat-row:last-child {
  border-bottom: none;
}

.stat-row__label {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.stat-row__value {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  transition: var(--transition);
}

.stat-row__value.bump {
  animation: score-bump 0.3s ease;
}

.stat-row--accent .stat-row__value {
  color: var(--accent-gold);
}

.stat-row--combo .stat-row__value {
  color: var(--accent-magenta);
  text-shadow: 0 0 10px rgba(255, 45, 149, 0.6);
}

@keyframes score-bump {
  0% { transform: scale(1); }
  50% { transform: scale(1.25); color: var(--accent-cyan); }
  100% { transform: scale(1); }
}

/* ─── Controls list ─── */
.controls-list {
  list-style: none;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.controls-list li {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0;
}

kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 1.6rem;
  padding: 0.15rem 0.4rem;
  font-family: var(--font-display);
  font-size: 0.65rem;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 4px;
  color: var(--text-primary);
}

/* ─── Game board ─── */
.board-section {
  position: relative;
  flex: 1;
  min-height: 0;
  min-width: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: stretch;
}

.board-frame {
  position: relative;
  flex: 1;
  width: 100%;
  min-height: 0;
  padding: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, rgba(0, 229, 255, 0.3), rgba(255, 45, 149, 0.3));
  border-radius: 8px;
  box-shadow:
    var(--glow-cyan),
    0 20px 60px rgba(0, 0, 0, 0.5);
  transition: box-shadow 0.3s ease;
}

.board-frame.board-pulse {
  animation: board-pulse 0.6s ease;
}

@keyframes board-pulse {
  0%, 100% { box-shadow: var(--glow-cyan), 0 20px 60px rgba(0, 0, 0, 0.5); }
  50% { box-shadow: 0 0 40px rgba(255, 45, 149, 0.6), 0 0 60px rgba(0, 229, 255, 0.4), 0 20px 60px rgba(0, 0, 0, 0.5); }
}

.board-frame__corner {
  position: absolute;
  width: 16px;
  height: 16px;
  border-color: var(--accent-cyan);
  border-style: solid;
  z-index: 3;
  pointer-events: none;
}

.board-frame__corner--tl { top: -2px; left: -2px; border-width: 2px 0 0 2px; }
.board-frame__corner--tr { top: -2px; right: -2px; border-width: 2px 2px 0 0; }
.board-frame__corner--bl { bottom: -2px; left: -2px; border-width: 0 0 2px 2px; }
.board-frame__corner--br { bottom: -2px; right: -2px; border-width: 0 2px 2px 0; }

#game-canvas,
#particle-canvas {
  display: block;
  border-radius: var(--board-radius);
  image-rendering: pixelated;
  image-rendering: crisp-edges;
  height: 100%;
  width: auto;
  max-height: 100%;
  max-width: 100%;
  aspect-ratio: 1 / 2;
}

#game-canvas {
  background: rgba(5, 8, 16, 0.95);
}

#particle-canvas {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  pointer-events: none;
  z-index: 2;
}

/* ─── Callouts & celebrations ─── */
.callout-layer {
  position: absolute;
  top: 50%;
  left: 50%;
  width: var(--board-display-w, 100%);
  height: var(--board-display-h, 100%);
  transform: translate(-50%, -50%);
  pointer-events: none;
  z-index: 5;
  overflow: hidden;
  border-radius: var(--board-radius);
}

.callout {
  position: absolute;
  left: 50%;
  top: 45%;
  transform: translate(-50%, -50%) scale(0.5);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 1.6rem;
  letter-spacing: 0.15em;
  white-space: nowrap;
  opacity: 0;
  text-shadow: 0 0 20px currentColor;
  transition: none;
}

.callout--visible {
  animation: callout-pop 1.2s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

.callout--exit {
  animation: callout-fade 0.4s ease forwards;
}

.callout--clear {
  color: var(--accent-cyan);
}

.callout--big {
  color: var(--accent-gold);
  font-size: 1.9rem;
}

.callout--tetris {
  color: var(--accent-magenta);
  font-size: 2.4rem;
  text-shadow: 0 0 30px var(--accent-magenta), 0 0 60px var(--accent-cyan);
}

.callout--level {
  color: var(--accent-purple);
  font-size: 1.4rem;
}

.callout--score {
  font-size: 1.1rem;
  color: var(--accent-gold);
  transform: translate(-50%, 0) scale(1);
  opacity: 0;
}

.callout--score.callout--visible {
  animation: score-float 0.9s ease forwards;
}

@keyframes callout-pop {
  0% { opacity: 0; transform: translate(-50%, -50%) scale(0.3); }
  30% { opacity: 1; transform: translate(-50%, -50%) scale(1.15); }
  60% { transform: translate(-50%, -50%) scale(1); }
  100% { opacity: 1; transform: translate(-50%, -55%) scale(1); }
}

@keyframes callout-fade {
  to { opacity: 0; transform: translate(-50%, -70%) scale(0.8); }
}

@keyframes score-float {
  0% { opacity: 0; transform: translate(-50%, 0) scale(0.8); }
  20% { opacity: 1; transform: translate(-50%, -10px) scale(1.1); }
  100% { opacity: 0; transform: translate(-50%, -50px) scale(0.9); }
}

/* ─── Level banner ─── */
.level-banner {
  position: absolute;
  top: -2rem;
  left: 50%;
  transform: translateX(-50%) scale(0);
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.3em;
  color: var(--accent-purple);
  text-shadow: 0 0 15px var(--accent-purple);
  z-index: 4;
  pointer-events: none;
  white-space: nowrap;
}

.level-banner--show {
  animation: level-banner 1.8s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

@keyframes level-banner {
  0% { transform: translateX(-50%) scale(0); opacity: 0; }
  20% { transform: translateX(-50%) scale(1.2); opacity: 1; }
  40% { transform: translateX(-50%) scale(1); }
  80% { opacity: 1; }
  100% { transform: translateX(-50%) scale(1); opacity: 0; top: -3rem; }
}

/* ─── Combo display ─── */
.combo-display {
  position: absolute;
  top: 50%;
  right: -5.5rem;
  transform: translateY(-50%) scale(0);
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--accent-magenta);
  writing-mode: vertical-rl;
  text-shadow: 0 0 12px var(--accent-magenta);
  z-index: 4;
  pointer-events: none;
}

.combo-display--show {
  animation: combo-show 1.5s ease forwards;
}

@keyframes combo-show {
  0% { transform: translateY(-50%) scale(0); opacity: 0; }
  20% { transform: translateY(-50%) scale(1.3); opacity: 1; }
  70% { opacity: 1; }
  100% { transform: translateY(-50%) scale(1); opacity: 0; }
}

/* ─── Screen shake ─── */
.shake-light { animation: shake 0.3s ease; }
.shake-medium { animation: shake 0.45s ease; }
.shake-heavy { animation: shake 0.6s ease; }

@keyframes shake {
  0%, 100% { transform: translate(0, 0); }
  15% { transform: translate(-3px, 2px); }
  30% { transform: translate(3px, -2px); }
  45% { transform: translate(-2px, -3px); }
  60% { transform: translate(2px, 3px); }
  75% { transform: translate(-1px, 1px); }
}

/* ─── Overlay ─── */
.overlay {
  position: absolute;
  top: 50%;
  left: 50%;
  width: var(--board-display-w, calc(100% - 8px));
  height: var(--board-display-h, calc(100% - 8px));
  transform: translate(-50%, -50%);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(5, 8, 16, 0.88);
  backdrop-filter: blur(6px);
  border-radius: var(--board-radius);
  z-index: 10;
  transition: opacity var(--transition), visibility var(--transition);
}

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

.overlay__content {
  text-align: center;
  padding: 2rem;
}

.overlay__title {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: title-shimmer 3s ease infinite;
  background-size: 200% 200%;
}

.overlay__subtitle {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

.btn {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 0.85rem 2rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: var(--transition);
}

.btn--primary {
  background: linear-gradient(135deg, var(--accent-cyan), #0099cc);
  color: var(--bg-deep);
  box-shadow: var(--glow-cyan);
  position: relative;
  overflow: hidden;
}

.btn--primary::after {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  transform: translateX(-100%);
  animation: btn-shine 3s ease infinite;
}

@keyframes btn-shine {
  0%, 70%, 100% { transform: translateX(-100%); }
  85% { transform: translateX(100%); }
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 30px rgba(0, 229, 255, 0.6);
}

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

.btn--auto {
  width: 100%;
  margin-bottom: 0.85rem;
  background: rgba(0, 229, 255, 0.08);
  color: var(--accent-cyan);
  border: 1px solid rgba(0, 229, 255, 0.25);
}

.btn--auto:hover {
  background: rgba(0, 229, 255, 0.14);
  box-shadow: var(--glow-cyan);
}

.btn--auto-active {
  background: linear-gradient(135deg, var(--accent-magenta), #cc0066);
  color: #fff;
  border-color: transparent;
  box-shadow: var(--glow-magenta);
}

.auto-badge {
  position: absolute;
  top: -0.5rem;
  right: -0.5rem;
  z-index: 5;
  padding: 0.25rem 0.6rem;
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--bg-deep);
  background: var(--accent-gold);
  border-radius: 4px;
  box-shadow: 0 0 12px rgba(255, 209, 102, 0.5);
  animation: auto-pulse 1.5s ease-in-out infinite;
}

@keyframes auto-pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.85; transform: scale(1.05); }
}

/* ─── Mobile controls ─── */
.mobile-controls {
  display: none;
  position: relative;
  z-index: 1;
  margin-top: 1.5rem;
  gap: 0.5rem;
  flex-wrap: wrap;
  justify-content: center;
  max-width: 320px;
}

.mob-btn {
  width: 56px;
  height: 56px;
  font-size: 1.25rem;
  font-family: var(--font-display);
  background: var(--bg-panel);
  border: 1px solid var(--bg-panel-border);
  border-radius: 12px;
  color: var(--text-primary);
  cursor: pointer;
  touch-action: manipulation;
  user-select: none;
  transition: var(--transition);
  backdrop-filter: blur(8px);
}

.mob-btn:active {
  background: rgba(0, 229, 255, 0.15);
  border-color: var(--accent-cyan);
  transform: scale(0.95);
}

.mob-btn--hard-drop {
  width: 100%;
  max-width: 180px;
  background: linear-gradient(135deg, rgba(255, 45, 149, 0.2), rgba(157, 78, 221, 0.2));
  border-color: rgba(255, 45, 149, 0.3);
}

/* ─── Footer ─── */
.footer {
  position: relative;
  z-index: 1;
  flex-shrink: 0;
  margin-top: 0.35rem;
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.1em;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.footer-link {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: var(--transition);
}

.footer-link:hover {
  text-shadow: 0 0 8px rgba(0, 229, 255, 0.5);
}

/* ─── Responsive ─── */
@media (max-width: 900px) {
  .panel--left .stat-card {
    display: none;
  }

  .panel--left {
    width: 100%;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    flex-shrink: 0;
  }

  .header--side {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 0.35rem 0.75rem;
    padding-bottom: 0;
    margin-bottom: 0;
    border-bottom: none;
    text-align: center;
  }

  .header--side .logo {
    flex-direction: row;
    align-items: center;
  }

  .header--side .logo__text {
    font-size: clamp(1rem, 3vw, 1.35rem);
  }

  .header--side .tagline,
  .header--side .help-link {
    margin-top: 0;
  }

  .game-layout {
    flex-wrap: wrap;
    align-content: stretch;
  }

  .panel--right .stat-card--controls {
    display: block;
    padding: 0;
    background: transparent;
    border: none;
    box-shadow: none;
    backdrop-filter: none;
  }

  .panel--right .stat-card--controls .stat-card__label,
  .panel--right .stat-card--controls .controls-list {
    display: none;
  }

  .panel--right .stat-card--controls .btn--auto {
    margin-bottom: 0;
    width: auto;
    min-width: 7rem;
  }

  .panel--right {
    width: auto;
  }

  .panel--right .stat-card:first-child {
    width: 120px;
  }

  .combo-display {
    right: -4rem;
    font-size: 0.65rem;
  }
}

@media (max-width: 600px) {
  .game-layout {
    flex-direction: column;
    align-items: center;
    min-height: 0;
  }

  .panel--left {
    width: 100%;
    order: -1;
  }

  .header--side .tagline {
    flex-basis: 100%;
  }

  .board-section {
    width: 100%;
    flex: 1;
  }

  .panel--right {
    flex-direction: row;
    width: auto;
    flex-shrink: 0;
    gap: 0.75rem;
  }

  .mobile-controls {
    display: flex;
    flex-shrink: 0;
    margin-top: 0.5rem;
  }

  .header--side .logo__text {
    letter-spacing: 0.18em;
  }
}

@media (min-width: 601px) {
  .mobile-controls {
    display: none;
  }
}