:root {
  --bg: #0b1020;
  --panel: rgba(255, 255, 255, 0.06);
  --panel2: rgba(255, 255, 255, 0.09);
  --text: rgba(255, 255, 255, 0.92);
  --muted: rgba(255, 255, 255, 0.72);
  --accent: #6ee7ff;
  --accent2: #a78bfa;
  --danger: #fb7185;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.45);
  --radius: 16px;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, "Helvetica Neue", Arial,
    "Noto Sans JP", "Hiragino Sans", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  color: var(--text);
  background: radial-gradient(1200px 600px at 10% 10%, rgba(167, 139, 250, 0.25), transparent 55%),
    radial-gradient(1000px 500px at 90% 20%, rgba(110, 231, 255, 0.18), transparent 60%),
    radial-gradient(900px 500px at 50% 90%, rgba(251, 113, 133, 0.12), transparent 65%), var(--bg);
}

.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 24px;
  display: grid;
  gap: 16px;
}

.header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.title {
  margin: 0;
  font-size: clamp(22px, 3vw, 32px);
  letter-spacing: 0.02em;
}

.subtitle {
  margin: 8px 0 0 0;
  color: var(--muted);
  line-height: 1.5;
}

.controls {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.button {
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(255, 255, 255, 0.08);
  color: var(--text);
  padding: 10px 14px;
  border-radius: 12px;
  cursor: pointer;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.25);
  transition: transform 120ms ease, background 120ms ease, border-color 120ms ease;
  user-select: none;
}

.button:hover {
  transform: translateY(-1px);
  background: rgba(255, 255, 255, 0.11);
  border-color: rgba(255, 255, 255, 0.24);
}

.button:active {
  transform: translateY(0px);
}

.button.primary {
  border-color: rgba(110, 231, 255, 0.35);
  background: linear-gradient(135deg, rgba(110, 231, 255, 0.18), rgba(167, 139, 250, 0.18));
}

.panel {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  padding: 14px;
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.stat {
  padding: 12px 12px;
  background: var(--panel2);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 14px;
}

.statLabel {
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.statValue {
  margin-top: 6px;
  font-size: 20px;
  font-variant-numeric: tabular-nums;
}

.game {
  display: grid;
  place-items: center;
}

.boardWrap {
  width: min(520px, 92vw);
  aspect-ratio: 1 / 1;
  padding: 14px;
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.board {
  height: 100%;
  width: 100%;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  outline: none;
}

.tile {
  display: grid;
  place-items: center;
  border-radius: 16px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.12), rgba(255, 255, 255, 0.06));
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.35);
  cursor: pointer;
  font-size: clamp(18px, 4vw, 36px);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: rgba(255, 255, 255, 0.92);
  user-select: none;
  transition: transform 120ms ease, border-color 120ms ease;
}

.tile:hover {
  transform: translateY(-1px);
  border-color: rgba(110, 231, 255, 0.35);
}

.tile:focus-visible {
  outline: 3px solid rgba(110, 231, 255, 0.55);
  outline-offset: 2px;
}

.tile.empty {
  background: transparent;
  border: 1px dashed rgba(255, 255, 255, 0.14);
  box-shadow: none;
  cursor: default;
}

.dialog {
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(11, 16, 32, 0.95);
  border-radius: 18px;
  color: var(--text);
  box-shadow: var(--shadow);
  padding: 0;
}

.dialog::backdrop {
  background: rgba(0, 0, 0, 0.5);
}

.dialogInner {
  padding: 18px;
  min-width: min(520px, 92vw);
}

.dialogTitle {
  margin: 0 0 8px 0;
}

.dialogText {
  margin: 0 0 14px 0;
  color: var(--muted);
}

.dialogButtons {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  flex-wrap: wrap;
}

.footer {
  display: flex;
  justify-content: center;
  padding-top: 6px;
}

.footerLink {
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
}

.footerLink:hover {
  color: rgba(255, 255, 255, 0.92);
  text-decoration: underline;
}

.srOnly {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

@media (max-width: 520px) {
  .panel {
    grid-template-columns: 1fr;
  }
  .controls {
    justify-content: flex-start;
  }
}