* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
}

:root {
  --purple-light: #cb90d5;
  --purple-container: #ce93d8;
  --on-purple-container: #1c1b1f;
  --peach-light: #ffeee6;
  --peach-container: #ffdccc;
  --on-peach-container: #973fa6;
  --mint-light: #e7fff3;
  --mint-container: #bff5dc;
  --on-mint-container: #123326;
  --background: #fff9e5;
  --on-background: #1c1b1f;
  --surface: #fff6f2;
  --surface-strong: #f8e5f9;
  --shadow: rgba(28, 27, 31, 0.14);
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  padding: 24px 16px;
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: Arial, sans-serif;
  background: linear-gradient(180deg, var(--background) 0%, var(--peach-light) 100%);
  color: var(--on-background);
  overflow-x: hidden;
}

.title-screen {
  position: fixed;
  inset: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: max(20px, env(safe-area-inset-top)) max(20px, env(safe-area-inset-right)) max(20px, env(safe-area-inset-bottom)) max(20px, env(safe-area-inset-left));
  background: linear-gradient(180deg, var(--background) 0%, var(--peach-light) 100%);
  opacity: 1;
  visibility: visible;
  transition: opacity 180ms ease, visibility 180ms ease;
}

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

.title-panel {
  width: min(100%, 520px);
  text-align: center;
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--on-peach-container);
  font-size: 0.78rem;
  font-weight: bold;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.title-copy {
  width: min(100%, 390px);
  margin: 0 auto 20px;
  line-height: 1.45;
  color: rgba(28, 27, 31, 0.78);
}

.pack-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 16px;
}

.pack-card {
  width: 100%;
  min-height: 176px;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 9px;
  padding: 10px;
  border: 2px solid rgba(206, 147, 216, 0.26);
  border-radius: 8px;
  background: var(--surface);
  color: var(--on-background);
  text-align: left;
  box-shadow: 0 5px 14px var(--shadow);
}

.pack-card[aria-pressed="true"] {
  border-color: var(--pack-accent);
  background: var(--mint-light);
  box-shadow: 0 8px 20px rgba(151, 63, 166, 0.18);
}

.pack-preview {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 5px;
}

.pack-preview-tile {
  aspect-ratio: 1 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  background: var(--pack-accent);
  background-image: var(--pack-image);
  background-position: center;
  background-size: cover;
  color: #ffffff;
  font-weight: bold;
  text-shadow: 0 1px 4px rgba(0, 0, 0, 0.34);
  overflow: hidden;
}

.pack-name {
  display: block;
  font-weight: bold;
  color: var(--on-background);
}

.pack-description {
  display: block;
  font-size: 0.8rem;
  line-height: 1.3;
  color: rgba(28, 27, 31, 0.7);
}

.start-btn {
  min-width: 150px;
  font-weight: bold;
}

.app {
  width: min(100%, 420px);
  text-align: center;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}

h1 {
  margin: 0 0 10px;
  font-size: 3rem;
  color: var(--on-peach-container);
}

.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.score-group {
  display: flex;
  gap: 10px;
}

.game-actions {
  display: flex;
  gap: 8px;
}

.score-box {
  background: var(--peach-container);
  color: var(--on-peach-container);
  padding: 10px 16px;
  border-radius: 8px;
  min-width: 90px;
  box-shadow: 0 4px 12px rgba(151, 63, 166, 0.14);
  transform: scale(1);
  transition: transform 120ms ease, filter 120ms ease;
}

.score-box.pulse {
  animation: scorePulse 220ms ease;
}

.score-label {
  font-size: 0.8rem;
  opacity: 0.9;
}

.score-value {
  font-size: 1.4rem;
  font-weight: bold;
  margin-top: 4px;
}

button {
  border: none;
  background: var(--purple-container);
  color: var(--on-purple-container);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 16px;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: bold;
  cursor: pointer;
  line-height: 1.15;
  transition: filter 120ms ease, transform 120ms ease, box-shadow 120ms ease;
  box-shadow: 0 4px 12px rgba(151, 63, 166, 0.14);
}

button:hover {
  filter: brightness(1.05);
}

button:active {
  transform: translateY(1px) scale(0.98);
  filter: brightness(0.98);
}

button:focus-visible {
  outline: 3px solid rgba(206, 147, 216, 0.45);
  outline-offset: 3px;
}

.instructions {
  margin: 0 0 14px;
  font-size: 0.95rem;
  line-height: 1.4;
  color: rgba(28, 27, 31, 0.75);
}

.board {
  width: 100%;
  margin-inline: auto;
  background: var(--purple-container);
  padding: 10px;
  border-radius: 10px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  position: relative;
  touch-action: none;
  overscroll-behavior: contain;
  box-shadow: 0 12px 28px rgba(151, 63, 166, 0.2);
}

.cell {
  aspect-ratio: 1 / 1;
  border-radius: 8px;
  background: rgba(255, 238, 230, 0.66);
  box-shadow: inset 0 0 0 1px rgba(255, 251, 254, 0.4);
}

.tile {
  position: absolute;
  z-index: 1;
  border-radius: 8px;
  font-size: 2rem;
  font-weight: bold;
  will-change: transform;
  overflow: hidden;
  --tile-bg: var(--peach-container);
  --tile-color: var(--on-background);
}

.tile-value {
  width: 100%;
  height: 100%;
  border-radius: inherit;
  display: flex;
  justify-content: center;
  align-items: center;
  background: var(--tile-bg);
  color: var(--tile-color);
}

.tile-has-image .tile-value {
  background-image: linear-gradient(rgba(28, 27, 31, 0.02), rgba(28, 27, 31, 0.08)), var(--tile-image);
  background-position: center;
  background-size: cover;
  color: transparent;
  overflow: hidden;
  text-shadow: none;
}

.tile-has-image::after {
  content: attr(data-tile-value);
  position: absolute;
  left: 7px;
  bottom: 7px;
  z-index: 2;
  min-width: 28px;
  padding: 4px 7px;
  border-radius: 999px;
  background: rgba(255, 251, 254, 0.9);
  color: var(--on-peach-container);
  font-size: 0.82rem;
  line-height: 1;
  text-align: center;
  box-shadow: 0 2px 8px rgba(28, 27, 31, 0.22);
}

.tile-moving {
  transition: transform 140ms ease-in-out;
}

.tile-spawn .tile-value {
  animation: tileSpawn 180ms ease-out;
}

.tile-merge .tile-value {
  animation: tileMerge 220ms ease-out;
}

.tile-2 { --tile-bg: var(--peach-light); --tile-color: var(--on-peach-container); }
.tile-4 { --tile-bg: var(--peach-container); --tile-color: var(--on-peach-container); }
.tile-8 { --tile-bg: var(--mint-light); --tile-color: var(--on-mint-container); }
.tile-16 { --tile-bg: var(--mint-container); --tile-color: var(--on-mint-container); }
.tile-32 { --tile-bg: #eac4ef; --tile-color: var(--on-purple-container); }
.tile-64 { --tile-bg: var(--purple-container); --tile-color: var(--on-purple-container); }
.tile-128 { --tile-bg: #f8d3c7; --tile-color: var(--on-peach-container); font-size: 1.7rem; }
.tile-256 { --tile-bg: #d4f7e6; --tile-color: var(--on-mint-container); font-size: 1.7rem; }
.tile-512 { --tile-bg: var(--purple-light); --tile-color: var(--on-purple-container); font-size: 1.7rem; }
.tile-1024 { --tile-bg: #ffd0bd; --tile-color: var(--on-peach-container); font-size: 1.3rem; }
.tile-2048 { --tile-bg: #b7efda; --tile-color: var(--on-mint-container); font-size: 1.3rem; }

.status {
  min-height: 28px;
  margin-top: 14px;
  font-weight: bold;
}

.overlay {
  position: fixed;
  inset: 0;
  z-index: 20;
  background: rgba(28, 27, 31, 0.35);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transition: opacity 180ms ease, visibility 180ms ease;
}

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

.overlay-card {
  background: var(--surface);
  color: var(--on-background);
  border-radius: 14px;
  padding: 24px;
  width: min(92vw, 360px);
  text-align: center;
  box-shadow: 0 12px 32px rgba(28, 27, 31, 0.22);
  transform: translateY(0) scale(1);
  transition: transform 180ms ease, opacity 180ms ease;
  opacity: 1;
}

.overlay.hidden .overlay-card {
  transform: translateY(10px) scale(0.96);
  opacity: 0;
}

.overlay-card h2 {
  margin-top: 0;
  margin-bottom: 10px;
}

.overlay-card p {
  margin: 0;
  line-height: 1.5;
}

.overlay-actions {
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 18px;
}

.secondary-btn {
  background: var(--mint-container);
  color: var(--on-mint-container);
}

@keyframes tileSpawn {
  0% {
    transform: scale(0.72);
  }
  70% {
    transform: scale(1.08);
  }
  100% {
    transform: scale(1);
  }
}

@keyframes tileMerge {
  0% {
    transform: scale(0.9);
  }
  45% {
    transform: scale(1.18);
  }
  100% {
    transform: scale(1);
  }
}

@keyframes scorePulse {
  0% {
    transform: scale(1);
    filter: brightness(1);
  }
  50% {
    transform: scale(1.08);
    filter: brightness(1.08);
  }
  100% {
    transform: scale(1);
    filter: brightness(1);
  }
}

@media (max-width: 600px) {
  body {
    align-items: flex-start;
    padding: max(12px, env(safe-area-inset-top)) max(12px, env(safe-area-inset-right)) max(12px, env(safe-area-inset-bottom)) max(12px, env(safe-area-inset-left));
  }

  .title-screen {
    align-items: flex-start;
    overflow-y: auto;
  }

  .title-panel {
    padding-bottom: 8px;
  }

  .title-copy {
    margin-bottom: 14px;
  }

  .pack-grid {
    grid-template-columns: 1fr;
    gap: 8px;
    margin-bottom: 14px;
  }

  .pack-card {
    min-height: 0;
    display: grid;
    grid-template-columns: clamp(72px, 24vw, 92px) 1fr;
    grid-template-rows: auto 1fr;
    column-gap: 10px;
    align-items: center;
    padding: 8px;
  }

  .pack-preview {
    grid-row: 1 / span 2;
  }

  .app {
    width: min(100%, 420px);
  }

  h1 {
    font-size: clamp(2rem, 10vw, 2.4rem);
    margin-bottom: 8px;
  }

  .top-bar {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    margin-bottom: 10px;
  }

  .game-actions {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
  }

  .score-group {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
  }

  .score-box {
    min-width: 0;
    padding: 8px 10px;
  }

  .score-label {
    font-size: 0.72rem;
  }

  .score-value {
    font-size: 1.2rem;
  }

  .pack-description {
    font-size: 0.76rem;
  }

  button {
    width: 100%;
    padding: 9px 10px;
    font-size: 0.95rem;
  }

  .instructions {
    font-size: 0.9rem;
    margin-bottom: 10px;
  }

  .board {
    padding: clamp(6px, 2.4vw, 10px);
    gap: clamp(6px, 2.4vw, 10px);
    border-radius: 8px;
  }

  .tile {
    font-size: 1.7rem;
    border-radius: 6px;
  }

  .cell {
    border-radius: 6px;
  }

  .tile-128,
  .tile-256,
  .tile-512 {
    font-size: 1.4rem;
  }

  .tile-1024,
  .tile-2048 {
    font-size: 1.1rem;
  }

  .overlay-actions button {
    width: 100%;
  }
}

@media (max-width: 360px) {
  body {
    padding-inline: 8px;
  }

  .game-actions {
    grid-template-columns: 1fr;
  }

  .instructions {
    font-size: 0.82rem;
  }

  .tile-has-image::after {
    left: 5px;
    bottom: 5px;
    min-width: 24px;
    padding: 3px 6px;
    font-size: 0.72rem;
  }
}

@media (max-height: 680px) and (max-width: 600px) {
  body {
    padding-block: 8px;
  }

  .instructions {
    margin-bottom: 8px;
  }

  .status {
    min-height: 20px;
    margin-top: 8px;
  }
}