:root {
  --bg: #050814;
  --accent: #6ee7b7;
  --accent-2: #7dd3fc;
  --muted: #9aa3b2;
  --glass: rgba(255, 255, 255, 0.04);
  --glass-2: rgba(255, 255, 255, 0.02);
  --win: #f59e0b;
  --shadow: 0 10px 30px rgba(2, 6, 23, 0.6);
  --glass-border: rgba(255, 255, 255, 0.06);
  --neon: 0 0 10px rgba(125, 211, 252, 0.12), 0 0 30px rgba(110, 231, 183, 0.06);
}

/* Page */
html,
body {
  height: 100%;
}
body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI",
    Roboto, "Helvetica Neue", Arial;
  background: radial-gradient(
      ellipse at 10% 10%,
      rgba(125, 211, 252, 0.03),
      transparent 10%
    ),
    linear-gradient(180deg, rgba(4, 6, 20, 0.9), rgba(3, 5, 15, 0.95));
  color: #e6eef6;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Canvas background area will paint starfield */
#bgCanvas {
  position: fixed;
  inset: 0;
  z-index: 0;
  display: block;
}

/* Main container */
.ui {
  position: relative;
  z-index: 2;
  display: flex;
  gap: 24px;
  align-items: flex-start;
  padding: 36px;
  height: 100vh;
  box-sizing: border-box;
}

.panel {
  width: 340px;
  min-width: 260px;
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.02),
    rgba(255, 255, 255, 0.01)
  );
  border-radius: 18px;
  padding: 20px;
  box-shadow: var(--shadow);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(8px) saturate(120%);
}

header h1 {
  margin: 0;
  font-size: 20px;
  letter-spacing: 0.4px;
}
header p {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.controls {
  display: flex;
  gap: 8px;
  margin-top: 16px;
}
.btn {
  appearance: none;
  border: 0;
  padding: 10px 14px;
  border-radius: 10px;
  cursor: pointer;
  background: var(--glass);
  color: var(--accent-2);
  font-weight: 600;
  box-shadow: var(--neon);
  border: 1px solid rgba(255, 255, 255, 0.03);
}
.btn.secondary {
  background: transparent;
  color: var(--muted);
  border: 1px solid rgba(255, 255, 255, 0.03);
}

/* Game board area */
.board-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}
.super-board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  width: min(760px, 90vmin);
  height: min(760px, 90vmin);
  padding: 18px;
  box-sizing: border-box;
  border-radius: 22px;
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.02),
    rgba(255, 255, 255, 0.01)
  );
  border: 1px solid var(--glass-border);
}

/* Mini boards */
.mini {
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.012),
    rgba(255, 255, 255, 0.008)
  );
  border-radius: 12px;
  padding: 10px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  position: relative;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.02);
}
.mini:hover {
  transform: translateY(-6px);
  box-shadow: 0 18px 40px rgba(2, 6, 23, 0.6);
}

.mini.locked {
  opacity: 0.42;
  filter: grayscale(0.3) contrast(0.8);
}

.cell {
  aspect-ratio: 1/1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.012),
    rgba(255, 255, 255, 0.01)
  );
  border-radius: 8px;
  font-size: 24px;
  font-weight: 700;
  cursor: pointer;
  user-select: none;
  transition: transform 0.12s ease, background 0.12s ease, box-shadow 0.12s ease;
  border: 1px solid rgba(255, 255, 255, 0.02);
}
.cell:active {
  transform: scale(0.96);
}

.mark.x {
  color: #ff7ab6;
  text-shadow: 0 4px 18px rgba(255, 122, 182, 0.12);
  font-size: 28px;
}
.mark.o {
  color: #7dd3fc;
  text-shadow: 0 4px 18px rgba(125, 211, 252, 0.08);
  font-size: 28px;
}

/* Highlight for active mini board */
.mini.active {
  outline: 3px solid rgba(125, 211, 252, 0.08);
  box-shadow: 0 10px 30px rgba(125, 211, 252, 0.02);
}

/* Big win overlay in mini board */
.mini.win::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 12px;
  background: linear-gradient(
    90deg,
    rgba(245, 158, 11, 0.06),
    rgba(126, 34, 206, 0.03)
  );
  pointer-events: none;
  animation: miniGlow 1.6s ease-in-out infinite;
}
@keyframes miniGlow {
  0% {
    opacity: 0;
  }
  50% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}

/* Global win animation */
.winner-banner {
  position: fixed;
  left: 50%;
  transform: translateX(-50%);
  top: 36px;
  z-index: 6;
  padding: 12px 20px;
  border-radius: 12px;
  font-weight: 700;
  letter-spacing: 0.6px;
  backdrop-filter: blur(6px);
  border: 1px solid rgba(255, 255, 255, 0.06);
  background: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0.02),
    rgba(255, 255, 255, 0.01)
  );
  box-shadow: 0 18px 44px rgba(2, 6, 23, 0.6);
}

/* small indicators */
.small {
  font-size: 13px;
  color: var(--muted);
}

/* win lines overlay (for super board) */
.lineCanvas {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 3;
}

/* responsive tweaks */
@media (max-width: 760px) {
  .ui {
    flex-direction: column;
    padding: 12px;
  }
  .panel {
    width: 100%;
    order: 2;
  }
  .board-wrap {
    order: 1;
    padding-top: 18px;
  }
  .super-board {
    gap: 8px;
  }
}

/* fancy constellation legend */
.legend {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-top: 16px;
}
.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  box-shadow: 0 6px 18px rgba(125, 211, 252, 0.08);
}

/* glowing turn indicator */
.turn {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 16px;
}
.turn .token {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-weight: 800;
  font-size: 18px;
}
.turn .token.x {
  background: linear-gradient(
    90deg,
    rgba(255, 122, 182, 0.12),
    rgba(255, 122, 182, 0.06)
  );
  color: #ff7ab6;
}
.turn .token.o {
  background: linear-gradient(
    90deg,
    rgba(125, 211, 252, 0.12),
    rgba(125, 211, 252, 0.06)
  );
  color: #7dd3fc;
}

/* subtle star twinkle animation for some backgrounds */
.twinkle {
  animation: twinkle 3s infinite;
}
@keyframes twinkle {
  0% {
    opacity: 0.6;
  }
  50% {
    opacity: 1;
  }
  100% {
    opacity: 0.6;
  }
}