:root {
  --board-size: min(82vw, 560px);
  --gap: clamp(8px, 1.8vw, 14px);
  --tile-size: calc((var(--board-size) - (var(--gap) * 5)) / 4);
  --radius-lg: 32px;
  --radius-md: 22px;
  --radius-sm: 16px;
  --move-duration: 230ms;
  --pop-duration: 180ms;
  --bg: #8fd6ee;
  --ink: #4b271b;
  --muted: #7e5a49;
  --cream: #fff4d8;
  --panel: rgba(255, 245, 221, 0.9);
  --wood: #b98860;
  --wood-dark: #835639;
  --rose: #f67676;
  --green: #97cf5a;
  --gold: #ffc741;
  --shadow: 0 22px 45px rgba(86, 61, 43, 0.22);
  --font: "Trebuchet MS", "Avenir Next", "Segoe UI", system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font);
  background:
    linear-gradient(rgba(255, 255, 255, 0.08), rgba(255, 246, 225, 0.3)),
    url("assets/garden-bg.png") center / cover fixed,
    var(--bg);
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    radial-gradient(circle at 15% 18%, rgba(255, 255, 255, 0.65) 0 2px, transparent 3px),
    radial-gradient(circle at 80% 22%, rgba(255, 235, 166, 0.75) 0 2px, transparent 3px),
    radial-gradient(circle at 68% 82%, rgba(255, 142, 166, 0.45) 0 3px, transparent 4px);
  opacity: 0.8;
}

button {
  border: 0;
  font: inherit;
  cursor: pointer;
}

button:focus-visible,
.board:focus-visible {
  outline: 4px solid rgba(83, 169, 232, 0.9);
  outline-offset: 4px;
}

.app-shell {
  min-height: 100vh;
  min-height: 100svh;
  display: grid;
  place-items: center;
  padding: clamp(16px, 3vw, 36px);
}

.game-card {
  width: min(1180px, 100%);
  padding: clamp(18px, 3vw, 30px);
  border: 3px solid rgba(255, 250, 233, 0.78);
  border-radius: var(--radius-lg);
  background:
    linear-gradient(135deg, rgba(255, 253, 242, 0.7), rgba(255, 242, 214, 0.48)),
    rgba(255, 255, 255, 0.35);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

.game-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: clamp(16px, 3vw, 28px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 18px;
}

.brand-mark {
  position: relative;
  display: grid;
  grid-template-columns: repeat(4, clamp(42px, 6vw, 64px));
  gap: 3px;
  padding: 10px 12px;
  border-radius: 28px;
  background: #fff4d8;
  border: 3px solid #fff;
  box-shadow: 0 9px 0 #d6a36b, 0 18px 26px rgba(91, 61, 34, 0.18);
  transform: rotate(-2deg);
}

.brand-mark::after {
  content: "✿";
  position: absolute;
  right: -12px;
  top: -16px;
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: #ff8f9c;
  color: #fffbe6;
  box-shadow: 0 4px 0 #cf686f;
}

.brand-mark span {
  display: grid;
  place-items: center;
  min-width: 0;
  height: clamp(44px, 6vw, 66px);
  border-radius: 18px;
  color: #fffdf1;
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 900;
  line-height: 1;
  text-shadow: 0 3px 0 rgba(79, 44, 32, 0.34);
  box-shadow: inset 0 3px rgba(255, 255, 255, 0.55), 0 4px 0 rgba(112, 70, 43, 0.18);
}

.brand-mark span:nth-child(1) { background: #f56f73; }
.brand-mark span:nth-child(2) { background: #ffc432; }
.brand-mark span:nth-child(3) { background: #56b7a2; }
.brand-mark span:nth-child(4) { background: #5fa7ee; }

h1,
h2,
p {
  margin: 0;
}

h1 {
  color: #8d59ca;
  font-size: clamp(46px, 7vw, 82px);
  font-weight: 900;
  line-height: 0.86;
  text-shadow: 0 4px 0 #fff2cf, 0 8px 0 rgba(91, 61, 34, 0.18);
}

.brand p {
  margin-top: 8px;
  color: var(--muted);
  font-size: clamp(15px, 2vw, 18px);
  font-weight: 800;
}

.scorebar {
  display: flex;
  align-items: stretch;
  justify-content: flex-end;
  flex-wrap: wrap;
  gap: 12px;
}

.score-card,
.new-game-button,
.modal-card,
.helper-panel,
.board-caption {
  border: 3px solid rgba(255, 255, 255, 0.72);
}

.score-card {
  min-width: 132px;
  padding: 13px 18px 12px;
  border-radius: 22px;
  background: linear-gradient(180deg, #fff8df, #fce8ba);
  box-shadow: 0 6px 0 #d99c51, 0 14px 22px rgba(89, 57, 35, 0.17);
  text-align: center;
}

.score-card span {
  display: block;
  color: #7f5636;
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

.score-card strong {
  display: block;
  margin-top: 3px;
  color: #4d271b;
  font-size: clamp(28px, 4vw, 38px);
  line-height: 1;
}

.best-card {
  background: linear-gradient(180deg, #fff8e5, #ffe0a5);
}

.new-game-button,
.modal-new-game-button,
.keep-playing-button {
  min-height: 58px;
  padding: 0 24px;
  border-radius: 22px;
  color: #fffdf1;
  font-size: 20px;
  font-weight: 900;
  text-shadow: 0 2px 0 rgba(97, 43, 39, 0.3);
  background: linear-gradient(180deg, #ff8984, #ed5f65);
  box-shadow: 0 7px 0 #b64d4b, 0 13px 22px rgba(114, 57, 49, 0.22);
  transition: transform 120ms ease, filter 120ms ease;
}

.new-game-button:hover,
.modal-new-game-button:hover,
.keep-playing-button:hover {
  transform: translateY(-2px);
  filter: saturate(1.08);
}

.new-game-button:active,
.modal-new-game-button:active,
.keep-playing-button:active {
  transform: translateY(4px);
  box-shadow: 0 3px 0 #b64d4b, 0 8px 14px rgba(114, 57, 49, 0.18);
}

.play-layout {
  display: grid;
  grid-template-columns: minmax(180px, 240px) minmax(0, var(--board-size));
  align-items: end;
  justify-content: center;
  gap: clamp(18px, 4vw, 44px);
}

.helper-panel {
  position: relative;
  padding: 24px 20px 22px;
  border-radius: 30px;
  background: linear-gradient(180deg, rgba(255, 253, 239, 0.94), rgba(255, 236, 204, 0.9));
  box-shadow: 0 10px 0 rgba(196, 145, 84, 0.55), 0 20px 30px rgba(92, 65, 42, 0.18);
  text-align: center;
}

.helper-panel::before,
.helper-panel::after {
  content: "✿";
  position: absolute;
  color: #ef7e8f;
  font-size: 28px;
}

.helper-panel::before {
  left: -10px;
  top: 18px;
}

.helper-panel::after {
  right: 16px;
  bottom: -12px;
}

.helper-panel p {
  margin-top: 14px;
  color: #6b4433;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.35;
}

.sprout-face {
  position: relative;
  width: 82px;
  height: 72px;
  margin: 0 auto;
  border-radius: 48% 52% 46% 54%;
  background: radial-gradient(circle at 32% 28%, #fff9a1 0 9%, transparent 10%), linear-gradient(145deg, #cbef6a, #86c54f);
  box-shadow: inset 0 4px rgba(255, 255, 255, 0.44), 0 8px 0 #5a993e;
}

.sprout-leaf {
  position: absolute;
  left: 31px;
  top: -24px;
  width: 24px;
  height: 30px;
  border-radius: 80% 0 80% 0;
  background: #77bd55;
  transform: rotate(28deg);
  box-shadow: -12px 7px 0 #8fd45f;
}

.sprout-eye {
  position: absolute;
  top: 34px;
  width: 9px;
  height: 13px;
  border-radius: 50%;
  background: #3f251f;
}

.sprout-eye.left { left: 24px; }
.sprout-eye.right { right: 24px; }

.sprout-mouth {
  position: absolute;
  left: 35px;
  bottom: 17px;
  width: 14px;
  height: 8px;
  border-radius: 0 0 999px 999px;
  background: #e55367;
}

.key-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 7px;
  margin-top: 16px;
}

.key-row span {
  display: grid;
  place-items: center;
  height: 34px;
  border-radius: 12px;
  color: #fffdf1;
  font-weight: 900;
  background: #84b95a;
  box-shadow: inset 0 2px rgba(255, 255, 255, 0.4), 0 4px 0 #5c8a3f;
}

.board-wrap {
  width: var(--board-size);
}

.board {
  position: relative;
  width: var(--board-size);
  height: var(--board-size);
  padding: var(--gap);
  border-radius: clamp(24px, 4vw, 36px);
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.18), transparent),
    repeating-linear-gradient(45deg, rgba(255, 255, 255, 0.08) 0 8px, transparent 8px 16px),
    linear-gradient(180deg, #d8ad7e, #a97750);
  border: 5px solid rgba(255, 239, 203, 0.95);
  box-shadow:
    inset 0 0 0 4px rgba(114, 73, 48, 0.25),
    0 11px 0 #7b5038,
    0 24px 42px rgba(64, 42, 30, 0.24);
  touch-action: none;
  user-select: none;
}

.grid,
.tile-layer {
  position: absolute;
  inset: var(--gap);
}

.grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(4, 1fr);
  gap: var(--gap);
}

.grid-cell {
  border-radius: clamp(15px, 3vw, 24px);
  background: rgba(255, 242, 209, 0.58);
  box-shadow: inset 0 4px 10px rgba(91, 61, 39, 0.12);
}

.tile {
  position: absolute;
  left: 0;
  top: 0;
  width: var(--tile-size);
  height: var(--tile-size);
  display: grid;
  place-items: center;
  border-radius: clamp(15px, 3vw, 24px);
  color: var(--ink);
  font-size: clamp(30px, calc(var(--tile-size) * 0.38), 58px);
  font-weight: 900;
  line-height: 1;
  text-shadow: 0 2px rgba(255, 255, 255, 0.58);
  transform: translate3d(calc(var(--x) * (var(--tile-size) + var(--gap))), calc(var(--y) * (var(--tile-size) + var(--gap))), 0);
  transition:
    transform var(--move-duration) cubic-bezier(0.16, 0.88, 0.22, 1),
    opacity 120ms ease;
  will-change: transform;
  box-shadow:
    inset 0 4px rgba(255, 255, 255, 0.42),
    inset 0 -5px rgba(88, 55, 38, 0.16),
    0 7px 0 rgba(83, 50, 34, 0.2);
  overflow: hidden;
}

.tile::before,
.tile::after {
  content: "";
  position: absolute;
  pointer-events: none;
}

.tile::before {
  left: 16%;
  bottom: 17%;
  width: 8%;
  height: 8%;
  border-radius: 50%;
  background: rgba(61, 34, 29, 0.92);
  box-shadow: calc(var(--tile-size) * 0.52) 0 0 rgba(61, 34, 29, 0.92);
}

.tile::after {
  right: 10%;
  top: 10%;
  width: 19%;
  height: 19%;
  border-radius: 50% 50% 50% 0;
  background: rgba(255, 255, 255, 0.62);
  transform: rotate(-18deg);
}

.tile span {
  position: relative;
  z-index: 1;
  transform: translateY(-5%);
}

.tile[data-value="2"] { background: linear-gradient(145deg, #fff6df, #f7dca9); }
.tile[data-value="4"] { background: linear-gradient(145deg, #ffe7bd, #f4bc78); }
.tile[data-value="8"] { background: linear-gradient(145deg, #ffb072, #f47c4f); color: #fffdf1; }
.tile[data-value="16"] { background: linear-gradient(145deg, #b8df73, #79b84c); color: #fffdf1; }
.tile[data-value="32"] { background: linear-gradient(145deg, #8ccdf6, #5b9fd6); color: #fffdf1; }
.tile[data-value="64"] { background: linear-gradient(145deg, #bea0f0, #8067d7); color: #fffdf1; }
.tile[data-value="128"] { background: linear-gradient(145deg, #ff8fa2, #e94f72); color: #fffdf1; }
.tile[data-value="256"] { background: linear-gradient(145deg, #ffd765, #f8a822); color: #fffdf1; }
.tile[data-value="512"] { background: linear-gradient(145deg, #e76bd9, #9b4bc2); color: #fffdf1; }
.tile[data-value="1024"] { background: linear-gradient(145deg, #58dbc1, #228c94); color: #fffdf1; font-size: clamp(24px, calc(var(--tile-size) * 0.28), 44px); }
.tile[data-value="2048"] { background: linear-gradient(145deg, #fff26f, #ff9f47 45%, #f06292); color: #fffdf1; font-size: clamp(24px, calc(var(--tile-size) * 0.28), 44px); }

.tile[data-value="128"],
.tile[data-value="256"],
.tile[data-value="512"],
.tile[data-value="1024"],
.tile[data-value="2048"] {
  text-shadow: 0 3px 0 rgba(78, 39, 32, 0.3), 0 0 12px rgba(255, 255, 255, 0.65);
  box-shadow:
    inset 0 4px rgba(255, 255, 255, 0.52),
    inset 0 -5px rgba(88, 55, 38, 0.14),
    0 7px 0 rgba(83, 50, 34, 0.2),
    0 0 24px rgba(255, 232, 113, 0.72);
}

.tile[data-value="2048"]::after {
  content: "✦";
  top: 6%;
  right: 9%;
  width: auto;
  height: auto;
  color: #fff;
  background: transparent;
  font-size: 24px;
  transform: none;
}

.tile.spawn {
  animation: spawn var(--pop-duration) cubic-bezier(0.2, 1.4, 0.28, 1) both;
}

.tile.merge {
  z-index: 3;
  animation: merge var(--pop-duration) cubic-bezier(0.2, 1.4, 0.28, 1) both;
}

.tile.merge-source {
  z-index: 2;
  animation: merge-source var(--move-duration) cubic-bezier(0.16, 0.88, 0.22, 1) both;
}

.board-caption {
  width: fit-content;
  max-width: 100%;
  margin: 18px auto 0;
  padding: 11px 20px;
  border-radius: 999px;
  color: #6b4433;
  font-size: 15px;
  font-weight: 900;
  text-align: center;
  background: rgba(255, 244, 216, 0.92);
  box-shadow: 0 6px 0 rgba(196, 145, 84, 0.45);
}

.modal {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 18px;
  background: rgba(68, 45, 35, 0.42);
  opacity: 0;
  visibility: hidden;
  transition: opacity 180ms ease, visibility 180ms ease;
  z-index: 10;
}

.modal.show {
  opacity: 1;
  visibility: visible;
}

.modal-card {
  width: min(420px, 100%);
  padding: 34px 28px 28px;
  border-radius: 34px;
  background:
    radial-gradient(circle at 20% 16%, rgba(255, 255, 255, 0.9) 0 0.4rem, transparent 0.45rem),
    linear-gradient(180deg, #fff8df, #ffedc6);
  box-shadow: 0 10px 0 #c48f57, 0 26px 54px rgba(50, 31, 24, 0.34);
  text-align: center;
  transform: translateY(18px) scale(0.94);
  transition: transform 180ms cubic-bezier(0.2, 1.35, 0.28, 1);
}

.modal.show .modal-card {
  transform: translateY(0) scale(1);
}

.modal-sprout {
  width: 76px;
  height: 64px;
  margin: 0 auto 12px;
  border-radius: 50%;
  background: linear-gradient(145deg, #d7f777, #8fc84f);
  box-shadow: inset 0 4px rgba(255, 255, 255, 0.45), 0 7px 0 #69973d;
}

.modal-card h2 {
  color: #f05f75;
  font-size: clamp(38px, 8vw, 56px);
  line-height: 0.95;
  text-shadow: 0 3px 0 #fff4cf, 0 6px 0 rgba(122, 69, 47, 0.13);
}

.modal-card p {
  margin: 14px auto 22px;
  max-width: 28ch;
  color: #6b4433;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.35;
}

.modal-actions {
  display: grid;
  gap: 12px;
}

.keep-playing-button {
  background: linear-gradient(180deg, #a8d86c, #73ad43);
  box-shadow: 0 7px 0 #57853a, 0 13px 22px rgba(70, 103, 39, 0.22);
}

.keep-playing-button:active {
  box-shadow: 0 3px 0 #57853a, 0 8px 14px rgba(70, 103, 39, 0.18);
}

@keyframes spawn {
  0% { opacity: 0; scale: 0.4; }
  100% { opacity: 1; scale: 1; }
}

@keyframes merge {
  0% { scale: 1; }
  55% { scale: 1.17; }
  100% { scale: 1; }
}

@keyframes merge-source {
  0% {
    opacity: 1;
    scale: 1;
  }
  72% {
    opacity: 0.96;
    scale: 1;
  }
  100% {
    opacity: 0;
    scale: 0.92;
  }
}

@media (max-width: 880px) {
  :root {
    --board-size: min(92vw, 520px);
  }

  body {
    background-attachment: scroll;
  }

  .game-header,
  .play-layout {
    grid-template-columns: 1fr;
  }

  .game-header {
    display: grid;
    justify-items: center;
    text-align: center;
  }

  .brand {
    justify-content: center;
    flex-wrap: wrap;
  }

  .scorebar {
    justify-content: center;
  }

  .play-layout {
    display: grid;
  }

  .helper-panel {
    order: 2;
    width: min(420px, 100%);
    margin: 4px auto 0;
    padding: 16px 18px;
  }

  .sprout-face {
    display: none;
  }

  .helper-panel p {
    margin-top: 0;
  }

  .key-row {
    display: none;
  }
}

@media (max-width: 540px) {
  :root {
    --board-size: min(calc(100vw - 50px), 390px);
    --gap: 8px;
  }

  .app-shell {
    align-items: start;
    padding: 10px;
  }

  .game-card {
    padding: 12px;
    border-radius: 24px;
  }

  .brand-mark {
    grid-template-columns: repeat(4, 40px);
    border-radius: 22px;
  }

  .brand-mark span {
    height: 42px;
    border-radius: 14px;
    font-size: 30px;
  }

  h1 {
    font-size: 54px;
  }

  .scorebar {
    display: grid;
    grid-template-columns: 1fr 1fr;
    width: 100%;
  }

  .score-card {
    min-width: 0;
    padding: 10px 12px;
  }

  .new-game-button {
    grid-column: 1 / -1;
    width: 100%;
  }

  .tile {
    border-radius: 15px;
  }

  .tile::before {
    opacity: 0.85;
  }

  .board-caption {
    font-size: 13px;
    padding: 9px 14px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    transition-duration: 1ms !important;
  }
}