:root {
  --bg: #070b16;
  --card: rgba(17, 24, 43, 0.72);
  --card-border: rgba(255, 255, 255, 0.12);
  --text: #e8ecf6;
  --muted: #9aa6c0;
  --p1: #6ea8fe;   /* X-seeker (player 1) */
  --p2: #f7a072;   /* O-seeker (player 2) */
  --x: #7cc4ff;
  --o: #ffd27c;
  --win: #66e6a6;
  --win2: #ff86c8;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

/* star background sits behind everything */
#particles-js {
  position: fixed;
  inset: 0;
  z-index: 0;
  background: radial-gradient(1200px 800px at 70% -10%, #131a30 0%, #070b16 60%);
}

.stage {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.card {
  width: 100%;
  max-width: 460px;
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: 18px;
  padding: 26px 24px;
  backdrop-filter: blur(10px);
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
}

h1 {
  margin: 0 0 4px;
  font-size: 1.7rem;
  text-align: center;
  letter-spacing: 0.3px;
}

.tagline {
  margin: 0 0 20px;
  text-align: center;
  color: var(--muted);
  font-size: 0.92rem;
}

fieldset {
  border: 1px solid var(--card-border);
  border-radius: 12px;
  margin: 0 0 16px;
  padding: 12px 14px 14px;
}

legend {
  padding: 0 6px;
  color: var(--muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

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

label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.82rem;
  color: var(--muted);
}

input, select {
  background: rgba(0, 0, 0, 0.28);
  border: 1px solid var(--card-border);
  color: var(--text);
  border-radius: 9px;
  padding: 8px 10px;
  font-size: 0.95rem;
  width: 100%;
}

input:focus, select:focus {
  outline: none;
  border-color: var(--p1);
}

.btn {
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  border-radius: 11px;
  padding: 11px 16px;
  font-size: 0.98rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.06s ease, background 0.15s ease, opacity 0.15s ease;
}
.btn:hover { background: rgba(255, 255, 255, 0.12); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

.btn.primary {
  width: 100%;
  background: linear-gradient(135deg, var(--p1), #a78bfa);
  border: none;
  color: #0a0f1e;
}
.btn.ghost { background: transparent; }

.tileX { border-color: var(--x); color: var(--x); }
.tileO { border-color: var(--o); color: var(--o); }


/* gameplay */
.status {
  text-align: center;
  font-weight: 600;
  margin-bottom: 14px;
  min-height: 1.3em;
}

.warning {
  margin-bottom: 14px;
  padding: 10px 12px;
  border-radius: 12px;
  font-size: 0.86rem;
  line-height: 1.35;
  text-align: center;
  color: #ffd27c;
  background: rgba(247, 160, 114, 0.12);
  border: 1px solid rgba(247, 160, 114, 0.4);
}

.board {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  justify-content: center;
  min-height: 44px;
  padding: 8px;
  border-radius: 12px;
  background: rgba(0, 0, 0, 0.25);
  margin-bottom: 16px;
}

.cell {
  width: 16px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 3px;
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-weight: 800;
  font-size: 1.05rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  animation: pop 0.12s ease;
}
.cell.X { color: var(--x); }
.cell.O { color: var(--o); }
.cell.win-0 {
  border-color: var(--win);
  box-shadow: 0 0 0 2px rgba(102, 230, 166, 0.45);
}
.cell.win-1 {
  border-color: var(--win2);
  box-shadow: 0 0 0 2px rgba(255, 134, 200, 0.45);
}

@keyframes pop {
  from { transform: scale(0.7); opacity: 0; }
  to   { transform: scale(1); opacity: 1; }
}

.controls {
  display: flex;
  gap: 12px;
}
.controls .btn { flex: 1; }

.result {
  text-align: center;
  font-size: 1.15rem;
  font-weight: 800;
  margin: 16px 0 6px;
  padding: 12px;
  border-radius: 12px;
  background: rgba(102, 230, 166, 0.12);
  border: 1px solid rgba(102, 230, 166, 0.4);
  color: var(--win);
}
.result.draw {
  background: rgba(154, 166, 192, 0.12);
  border-color: rgba(154, 166, 192, 0.4);
  color: var(--muted);
}

.actions {
  display: flex;
  justify-content: center;
  margin-top: 12px;
}

@media (max-width: 420px) {
  .card { padding: 20px 16px; }
}