:root {
  color-scheme: dark;
  font-family: "Avenir Next", "Segoe UI", sans-serif;
  --bg-0: #07111f;
  --bg-1: #0e1f34;
  --bg-2: #1d1035;
  --panel: rgba(8, 19, 35, 0.8);
  --panel-border: rgba(173, 230, 255, 0.18);
  --text: #ecf7ff;
  --muted: #9db9d7;
  --accent: #7cf8cf;
  --piece-i: linear-gradient(180deg, #8af7ff 0%, #31d1ff 100%);
  --piece-o: linear-gradient(180deg, #ffe27c 0%, #ffbb33 100%);
  --piece-t: linear-gradient(180deg, #ff8bf4 0%, #d457ff 100%);
  --piece-s: linear-gradient(180deg, #8affb8 0%, #34d97a 100%);
  --piece-z: linear-gradient(180deg, #ff8b9b 0%, #ff4f67 100%);
  --piece-j: linear-gradient(180deg, #8db4ff 0%, #4573ff 100%);
  --piece-l: linear-gradient(180deg, #ffc17a 0%, #ff8a2b 100%);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(86, 225, 255, 0.18), transparent 30%),
    radial-gradient(circle at top right, rgba(194, 114, 255, 0.16), transparent 26%),
    linear-gradient(140deg, var(--bg-0), var(--bg-1) 45%, var(--bg-2));
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: radial-gradient(circle at center, black 45%, transparent 100%);
  pointer-events: none;
}

.app {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 28px 18px 36px;
}

.shell {
  width: min(1120px, 100%);
  display: grid;
  gap: 22px;
}

.hero {
  display: grid;
  gap: 10px;
}

.eyebrow {
  margin: 0;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.78rem;
}

.hero h1 {
  margin: 0;
  font-family: "Avenir Next Condensed", "Arial Narrow", sans-serif;
  font-size: clamp(2.8rem, 5vw, 5rem);
  line-height: 0.92;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.lead {
  margin: 0;
  max-width: 60ch;
  color: var(--muted);
  font-size: 1rem;
}

.layout {
  display: grid;
  grid-template-columns: minmax(320px, 1.1fr) minmax(280px, 0.85fr);
  gap: 22px;
}

.panel {
  border: 1px solid var(--panel-border);
  background: var(--panel);
  border-radius: 28px;
  box-shadow:
    0 24px 60px rgba(0, 0, 0, 0.28),
    inset 0 1px 0 rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(16px);
}

.stage-panel {
  padding: 22px;
}

.panel-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 18px;
}

.panel-head h2,
.panel-head p {
  margin: 0;
}

.panel-head p {
  color: var(--muted);
}

.status {
  margin-top: 18px;
  padding: 14px 16px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.05);
  color: #d9ecff;
  line-height: 1.45;
}

.board-shell {
  margin-top: 18px;
  padding: 16px;
  border-radius: 28px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.04), transparent 18%),
    linear-gradient(180deg, rgba(14, 31, 52, 0.96), rgba(6, 12, 24, 0.98));
  box-shadow: inset 0 0 0 1px rgba(124, 248, 207, 0.08);
}

.board {
  --cols: 10;
  display: grid;
  grid-template-columns: repeat(var(--cols), minmax(0, 1fr));
  gap: 4px;
  aspect-ratio: 1 / 2;
}

.cell,
.preview-cell {
  position: relative;
  overflow: hidden;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.04);
  box-shadow: inset 0 0 0 1px rgba(124, 171, 214, 0.08);
}

.cell::after,
.preview-cell::after {
  content: "";
  position: absolute;
  inset: 1px;
  border-radius: 7px;
  opacity: 0;
  transition: opacity 120ms ease, transform 120ms ease;
}

.filled::after,
.ghost::after {
  opacity: 1;
}

.is-current::after {
  transform: translateY(-1px);
  filter: brightness(1.08);
}

.ghost::after {
  opacity: 0.28;
}

.piece-i::after {
  background: var(--piece-i);
}

.piece-o::after {
  background: var(--piece-o);
}

.piece-t::after {
  background: var(--piece-t);
}

.piece-s::after {
  background: var(--piece-s);
}

.piece-z::after {
  background: var(--piece-z);
}

.piece-j::after {
  background: var(--piece-j);
}

.piece-l::after {
  background: var(--piece-l);
}

.side-panel {
  padding: 22px;
  display: grid;
  align-content: start;
  gap: 18px;
}

.card {
  padding: 16px;
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.04);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
}

.card-label {
  margin: 0 0 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.8rem;
}

.next-board {
  --cols: 4;
  display: grid;
  grid-template-columns: repeat(var(--cols), minmax(0, 1fr));
  gap: 5px;
  width: min(100%, 180px);
  aspect-ratio: 1;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.stat {
  padding: 14px 16px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.04);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
}

.stat span {
  display: block;
  color: var(--muted);
  font-size: 0.85rem;
}

.stat strong {
  display: block;
  margin-top: 6px;
  font-size: 1.5rem;
  font-weight: 700;
}

.actions,
.controls {
  display: grid;
  gap: 12px;
}

.actions {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.actions .wide {
  grid-column: span 2;
}

.controls {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.controls .wide {
  grid-column: span 3;
}

button {
  border: 0;
  border-radius: 16px;
  padding: 13px 14px;
  color: var(--text);
  background:
    linear-gradient(180deg, rgba(126, 235, 216, 0.18), rgba(38, 90, 109, 0.22)),
    rgba(255, 255, 255, 0.05);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.12),
    0 10px 24px rgba(0, 0, 0, 0.2);
  font: inherit;
  cursor: pointer;
  transition: transform 120ms ease, filter 120ms ease;
}

button:hover {
  filter: brightness(1.08);
}

button:active {
  transform: translateY(1px);
}

.button-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 16px;
  padding: 13px 14px;
  color: var(--text);
  text-decoration: none;
  background:
    linear-gradient(180deg, rgba(126, 235, 216, 0.18), rgba(38, 90, 109, 0.22)),
    rgba(255, 255, 255, 0.05);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.12),
    0 10px 24px rgba(0, 0, 0, 0.2);
}

a {
  color: var(--accent);
}

.meta,
.strategy,
.help {
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
}

.strategy {
  color: #dcecff;
}

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .stats-grid,
  .actions {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .app {
    padding-inline: 12px;
  }

  .stage-panel,
  .side-panel {
    padding: 16px;
  }

  .panel-head {
    flex-direction: column;
    align-items: start;
  }

  .controls {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .controls .wide {
    grid-column: span 2;
  }
}