:root {
  --bg: #0f1220;
  --panel: #151934;
  --panel-2: #131733;
  --text: #e8ecf1;
  --muted: #9aa4b2;
  --primary: #4f8cff;
  --primary-600: #3c74e6;
  --accent: #22d3ee;
  --danger: #ef4444;
  --win: #22c55e;
  --cell: #1a1f45;
  --cell-border: #2a2f58;
  --shadow: 0 10px 30px rgba(5, 10, 30, 0.5);
}

[data-theme="light"] {
  --bg: #f5f7fb;
  --panel: #ffffff;
  --panel-2: #ffffff;
  --text: #0b1220;
  --muted: #5b6576;
  --primary: #2563eb;
  --primary-600: #1e4fd1;
  --accent: #0891b2;
  --danger: #dc2626;
  --win: #16a34a;
  --cell: #ffffff;
  --cell-border: #d4d8e3;
  --shadow: 0 8px 26px rgba(14, 17, 49, 0.12);
}

* {
  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;
  background: radial-gradient(1200px 800px at 20% -10%, #1b1f3b 0%, var(--bg) 45%),
    radial-gradient(1000px 600px at 120% 10%, #17203a 0%, transparent 40%);
  color: var(--text);
  display: grid;
  place-items: center;
  padding: 24px;
}

.container {
  width: 100%;
  max-width: 880px;
  background: linear-gradient(180deg, var(--panel) 0%, var(--panel-2) 100%);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 20px 20px 24px;
}

header {
  margin-bottom: 10px;
  text-align: center;
}

header h1 {
  margin: 0 0 6px;
  font-size: 28px;
  letter-spacing: 0.3px;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.controls {
  margin-top: 12px;
  text-align: center;
}

.controls .row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
}

.controls .actions {
  margin-top: 10px;
}

.control {
  display: grid;
  gap: 6px;
}

.control span {
  font-size: 12px;
  color: var(--muted);
}

.control select {
  appearance: none;
  padding: 10px 14px;
  border-radius: 10px;
  background: var(--cell);
  color: var(--text);
  border: 1px solid var(--cell-border);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04);
}

.btn {
  appearance: none;
  border: 1px solid var(--cell-border);
  background: var(--cell);
  color: var(--text);
  padding: 10px 14px;
  border-radius: 10px;
  cursor: pointer;
  transition: transform .08s ease, border-color .15s ease, background .2s ease;
}

.btn:hover {
  transform: translateY(-1px);
  border-color: var(--primary);
}

.btn:active {
  transform: translateY(0);
}

.btn.primary {
  background: linear-gradient(180deg, var(--primary) 0%, var(--primary-600) 100%);
  border-color: transparent;
}

.btn.danger {
  background: linear-gradient(180deg, #f87171 0%, var(--danger) 100%);
  border-color: transparent;
}

.btn.ghost {
  background: transparent;
}

.btn.icon {
  padding: 8px 10px;
}

.status {
  margin: 14px 2px;
  font-size: 14px;
  color: var(--muted);
}

.board {
  --size: min(80vw, 420px);
  margin: 10px auto 14px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 10px;
  width: var(--size);
  height: var(--size);
}

.cell {
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: clamp(36px, 11vw, 64px);
  background: radial-gradient(200px 120px at 50% 0%, rgba(255, 255, 255, 0.06), transparent), var(--cell);
  border: 1px solid var(--cell-border);
  color: var(--text);
  border-radius: 14px;
  cursor: pointer;
  transition: transform .08s ease, box-shadow .15s ease, background .2s ease;
  box-shadow: inset 0 -2px 0 rgba(255, 255, 255, 0.04);
}

.cell:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 18px rgba(0, 0, 0, 0.2);
}

.cell:disabled {
  opacity: .5;
  cursor: not-allowed;
}

.cell.x {
  color: var(--primary);
  text-shadow: 0 2px 0 rgba(0, 0, 0, 0.2);
}

.cell.o {
  color: var(--accent);
  text-shadow: 0 2px 0 rgba(0, 0, 0, 0.2);
}

.cell.win {
  outline: 2px solid var(--win);
  box-shadow: 0 0 0 3px rgba(34, 197, 94, .25);
}

.cell.hint {
  outline: 2px dashed var(--accent);
  box-shadow: 0 0 0 3px rgba(34, 211, 238, .25);
}

.scoreboard {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.04), transparent);
  border: 1px dashed var(--cell-border);
  border-radius: 12px;
  padding: 10px 12px;
}

.score {
  margin: 0;
  text-align: center;
  font-size: 14px;
}

/* Modal */
.modal[hidden] {
  display: none;
}

.modal {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  z-index: 20;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, .5);
  -webkit-backdrop-filter: blur(2px);
  backdrop-filter: blur(2px);
}

.modal-content {
  position: relative;
  z-index: 21;
  width: min(92vw, 560px);
  background: var(--panel);
  color: var(--text);
  border-radius: 14px;
  border: 1px solid var(--cell-border);
  box-shadow: var(--shadow);
}

.modal-header,
.modal-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  border-bottom: 1px solid var(--cell-border);
}

.modal-footer {
  border-top: 1px solid var(--cell-border);
  border-bottom: none;
  justify-content: flex-end;
}

.modal-body {
  padding: 14px 16px;
  color: var(--muted);
}

.modal-body ul {
  margin: 8px 0 0 18px;
}

/* Focus styles */
button:focus-visible,
select:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

/* Responsive tweaks */
@media (max-width: 520px) {
  .controls .row {
    gap: 8px;
  }

  .btn {
    padding: 9px 12px;
  }
}