:root {
  --ink: #07150f;
  --paper: #f5f2e9;
  --lime: #c8ff62;
  --mint: #8fffc4;
  --muted: #95a19a;
  --line: rgba(255, 255, 255, 0.14);
  --panel: rgba(255, 255, 255, 0.045);
  --radius: 26px;
  --font: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
}

body {
  position: relative;
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  color: var(--paper);
  background: var(--ink);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
}

button,
a {
  font: inherit;
  -webkit-tap-highlight-color: transparent;
}

a {
  color: inherit;
  text-decoration: none;
}

button:focus-visible,
a:focus-visible {
  outline: 3px solid var(--mint);
  outline-offset: 4px;
}

.ambient {
  position: fixed;
  z-index: -1;
  border-radius: 50%;
  filter: blur(10px);
  pointer-events: none;
}

.ambient-one {
  top: -24rem;
  right: -12rem;
  width: 64rem;
  height: 64rem;
  background: radial-gradient(circle, rgba(143, 255, 196, 0.16), transparent 66%);
}

.ambient-two {
  bottom: -28rem;
  left: -18rem;
  width: 60rem;
  height: 60rem;
  background: radial-gradient(circle, rgba(200, 255, 98, 0.09), transparent 66%);
}

.shell {
  width: min(1160px, calc(100% - 40px));
  margin-inline: auto;
}

.site-header {
  padding: 22px 0;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -0.035em;
}

.brand-mark {
  display: grid;
  min-width: 64px;
  height: 36px;
  padding: 0 12px;
  place-items: center;
  color: var(--ink);
  background: var(--lime);
  border-radius: 999px;
  font-size: 9px;
  font-weight: 950;
  letter-spacing: 0.035em;
}

.edition {
  color: #859089;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.18em;
}

.layout {
  display: grid;
  grid-template-columns: minmax(290px, 0.72fr) minmax(460px, 1.28fr);
  align-items: center;
  gap: clamp(38px, 7vw, 92px);
  min-height: calc(100vh - 81px);
  padding: 36px 0 70px;
}

.intro {
  padding-bottom: 18px;
}

.eyebrow,
.panel-label {
  color: #cdd5d0;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 24px;
}

.eyebrow span {
  width: 8px;
  height: 8px;
  background: var(--lime);
  border-radius: 50%;
  box-shadow: 0 0 0 5px rgba(200, 255, 98, 0.12);
}

h1 {
  margin: 0;
  font-size: clamp(46px, 6vw, 82px);
  letter-spacing: -0.065em;
  line-height: 0.98;
}

h1 em {
  color: transparent;
  background: linear-gradient(105deg, var(--lime), var(--mint) 55%, #69d9ff);
  background-clip: text;
  -webkit-background-clip: text;
  font-style: normal;
}

.lead {
  max-width: 460px;
  margin: 25px 0 0;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.78;
}

.stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 32px;
}

.stat-card {
  padding: 17px 18px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 17px;
}

.stat-card span {
  display: block;
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 700;
}

.stat-card strong {
  display: block;
  overflow: hidden;
  font-size: clamp(24px, 4vw, 34px);
  font-variant-numeric: tabular-nums;
  font-weight: 850;
  letter-spacing: -0.045em;
  text-overflow: ellipsis;
}

.controls {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 10px;
}

.button {
  display: inline-flex;
  min-height: 52px;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 0 20px;
  color: var(--paper);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 999px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 800;
  transition:
    transform 180ms ease,
    background 180ms ease,
    border-color 180ms ease;
}

.button:hover:not(:disabled) {
  border-color: rgba(255, 255, 255, 0.28);
  transform: translateY(-2px);
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.38;
}

.button-primary {
  color: var(--ink);
  background: var(--lime);
  border-color: var(--lime);
}

.button-primary:hover:not(:disabled) {
  background: #dcffa1;
  border-color: #dcffa1;
}

.guide {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 26px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.guide-item {
  display: flex;
  align-items: flex-start;
  gap: 11px;
}

.guide-icon {
  display: grid;
  width: 31px;
  height: 31px;
  flex: 0 0 auto;
  place-items: center;
  color: var(--lime);
  background: rgba(200, 255, 98, 0.08);
  border-radius: 9px;
  font-size: 13px;
}

.guide p {
  margin: 0;
  color: var(--muted);
  font-size: 11px;
  line-height: 1.5;
}

.guide strong {
  display: block;
  margin-bottom: 2px;
  color: #dce2de;
  font-size: 12px;
}

.game-column {
  min-width: 0;
}

.board-wrap {
  padding: clamp(18px, 3vw, 30px);
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.06), rgba(255, 255, 255, 0.018)),
    rgba(7, 21, 15, 0.82);
  border: 1px solid rgba(255, 255, 255, 0.17);
  border-radius: 30px;
  box-shadow:
    0 32px 100px rgba(0, 0, 0, 0.35),
    inset 0 1px 0 rgba(255, 255, 255, 0.07);
}

.board-top {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 20px;
}

.panel-label {
  margin: 0 0 5px;
  color: #83918a;
  font-size: 9px;
}

.board-top h2 {
  margin: 0;
  font-size: clamp(20px, 3vw, 28px);
  letter-spacing: -0.04em;
}

.progress {
  display: flex;
  align-items: flex-end;
  flex-direction: column;
}

.progress span {
  color: var(--lime);
  font-size: 24px;
  font-variant-numeric: tabular-nums;
  font-weight: 850;
  letter-spacing: -0.05em;
}

.progress small {
  color: #77847d;
  font-size: 8px;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.board {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(7px, 1.5vw, 12px);
  width: 100%;
  aspect-ratio: 1;
  padding: clamp(7px, 1.5vw, 12px);
  background:
    linear-gradient(rgba(255, 255, 255, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.025) 1px, transparent 1px),
    #0a1d14;
  background-size: 32px 32px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 21px;
  touch-action: none;
  user-select: none;
}

.cell {
  position: relative;
  display: grid;
  overflow: hidden;
  place-items: center;
  background: rgba(255, 255, 255, 0.035);
  border: 1px solid rgba(255, 255, 255, 0.035);
  border-radius: clamp(12px, 2.2vw, 20px);
}

.tile {
  display: grid;
  width: 100%;
  height: 100%;
  place-items: center;
  border-radius: inherit;
  font-size: clamp(23px, 4.8vw, 49px);
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.07em;
  line-height: 1;
  transform: scale(1);
}

.tile.empty {
  color: transparent;
  background: transparent;
}

.tile.pop {
  animation: tile-pop 190ms ease-out;
}

.tile.merged {
  animation: tile-merge 270ms ease-out;
}

.tile.v2,
.tile.v4 {
  color: var(--ink);
  background: linear-gradient(145deg, #f7f3e8, #d8ddc7);
}

.tile.v8 {
  color: var(--ink);
  background: linear-gradient(145deg, #d7ff8c, #b7e855);
}

.tile.v16 {
  color: var(--ink);
  background: linear-gradient(145deg, #c8ff62, #8be76e);
}

.tile.v32 {
  color: var(--ink);
  background: linear-gradient(145deg, #92ffc4, #40cf96);
}

.tile.v64 {
  color: var(--ink);
  background: linear-gradient(145deg, #79e9ff, #43b7d8);
}

.tile.v128 {
  color: var(--ink);
  background: linear-gradient(145deg, #c2b7ff, #9182f0);
}

.tile.v256 {
  color: #fff;
  background: linear-gradient(145deg, #7671d9, #4c479a);
}

.tile.v512 {
  color: #fff;
  background: linear-gradient(145deg, #3d604e, #244334);
}

.tile.v1024 {
  color: var(--ink);
  background: linear-gradient(145deg, #fff4a4, #f5bf52);
  box-shadow: 0 0 30px rgba(245, 191, 82, 0.24);
}

.tile.v2048 {
  color: var(--ink);
  background: linear-gradient(145deg, #f4ff9c, #c8ff62);
  box-shadow: 0 0 40px rgba(200, 255, 98, 0.45);
}

.tile.v4096,
.tile.v8192 {
  color: #fff;
  background: linear-gradient(145deg, #ff9f78, #d65370);
  box-shadow: 0 0 36px rgba(255, 92, 108, 0.25);
}

@keyframes tile-pop {
  0% {
    opacity: 0;
    transform: scale(0.65);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes tile-merge {
  0% {
    transform: scale(0.88);
  }
  55% {
    transform: scale(1.08);
  }
  100% {
    transform: scale(1);
  }
}

.board-note {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-top: 15px;
  color: #7f8c85;
  font-size: 9px;
}

.board-note span {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
}

.dot-green {
  background: var(--lime);
}

.dot-white {
  background: #dce2de;
}

.tip {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-top: 14px;
  padding: 15px 18px;
  background: rgba(255, 255, 255, 0.025);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.tip-number {
  flex: 0 0 auto;
  color: var(--lime);
  font-size: 9px;
  font-weight: 900;
  letter-spacing: 0.12em;
}

.tip p {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  padding: 20px;
  place-items: center;
  background: rgba(4, 14, 9, 0.76);
  backdrop-filter: blur(14px);
}

.modal[hidden] {
  display: none;
}

.modal-card {
  position: relative;
  width: min(470px, 100%);
  overflow: hidden;
  padding: 42px;
  text-align: center;
  background: #0d2118;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 28px;
  box-shadow: 0 34px 100px rgba(0, 0, 0, 0.5);
}

.modal-orbit {
  position: absolute;
  top: -160px;
  left: 50%;
  width: 330px;
  height: 330px;
  border: 1px solid rgba(200, 255, 98, 0.13);
  border-radius: 50%;
  transform: translateX(-50%);
}

.modal-card > * {
  position: relative;
}

.modal-card h2 {
  margin: 7px 0 14px;
  font-size: clamp(34px, 7vw, 52px);
  letter-spacing: -0.055em;
}

.modal-card > p:not(.panel-label) {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
}

.modal-score {
  margin: 26px 0;
  padding: 16px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.modal-score span {
  display: block;
  color: var(--muted);
  font-size: 11px;
}

.modal-score strong {
  display: block;
  margin-top: 2px;
  color: var(--lime);
  font-size: 32px;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.05em;
}

.modal-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

@media (max-width: 880px) {
  .layout {
    grid-template-columns: 1fr;
    max-width: 650px;
    padding-top: 18px;
  }

  .intro {
    padding-bottom: 0;
  }

  .lead {
    max-width: 100%;
  }

  .game-column {
    width: 100%;
  }
}

@media (max-width: 540px) {
  .shell {
    width: min(100% - 24px, 1160px);
  }

  .site-header {
    padding: 16px 0;
  }

  .layout {
    gap: 28px;
    padding-bottom: 34px;
  }

  h1 {
    font-size: clamp(47px, 15vw, 72px);
  }

  .lead {
    font-size: 14px;
  }

  .stats {
    margin-top: 25px;
  }

  .board-wrap {
    padding: 14px;
    border-radius: 22px;
  }

  .board {
    border-radius: 16px;
  }

  .cell {
    border-radius: 12px;
  }

  .tile {
    font-size: clamp(25px, 9vw, 43px);
  }

  .board-note {
    align-items: flex-start;
    flex-direction: column;
    gap: 7px;
  }

  .guide {
    grid-template-columns: 1fr;
  }

  .modal-card {
    padding: 34px 24px 26px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}