/* Lightweight styling, independent from the main page */
:root{
  --bg:#0b1220;
  --surface:rgba(255,255,255,0.06);
  --surface2:rgba(255,255,255,0.10);
  --text:#e9eefc;
  --muted:rgba(233,238,252,0.72);
  --border:rgba(255,255,255,0.14);
  --primary:#7c5cff;
  --primary2:#a38bff;
  --shadow:0 12px 30px rgba(0,0,0,0.35);
  --r:18px;
  --font: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial;
}
:root[data-theme="light"]{
  --bg:#f7f8fe;
  --surface:rgba(13,20,44,0.05);
  --surface2:rgba(13,20,44,0.08);
  --text:#0d142c;
  --muted:rgba(13,20,44,0.70);
  --border:rgba(13,20,44,0.12);
  --primary:#4b2cff;
  --primary2:#6b55ff;
  --shadow:0 12px 30px rgba(13, 20, 44, 0.15);
}

*{ box-sizing: border-box; }
body{
  margin:0;
  font-family: var(--font);
  background: radial-gradient(1100px 600px at 20% 10%, rgba(124,92,255,0.35), transparent 60%),
              radial-gradient(900px 600px at 80% 20%, rgba(163,139,255,0.22), transparent 55%),
              var(--bg);
  color: var(--text);
}
a{ color: inherit; text-decoration: none; }
a:hover{ text-decoration: underline; }

.container{
  width: min(1080px, calc(100% - 2rem));
  margin: 0 auto;
}

.topbar{
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--border);
  background: rgba(0,0,0,0.18);
  backdrop-filter: blur(10px);
}
:root[data-theme="light"] .topbar{ background: rgba(247,248,254,0.70); }

.topbar .container{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 0;
}
.back{
  border: 1px solid var(--border);
  background: var(--surface);
  padding: 0.55rem 0.8rem;
  border-radius: 14px;
}
.title .h1{ font-weight: 850; font-size: 1.2rem; }
.title .sub{ font-size: 0.9rem; color: var(--muted); margin-top: -2px; }

.btn{
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  border-radius: 16px;
  padding: 0.65rem 0.9rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 120ms ease, background 120ms ease;
}
.btn:active{ transform: translateY(1px); }
.btn:hover{ background: var(--surface2); }
.btn-primary{
  border-color: transparent;
  background: linear-gradient(135deg, var(--primary), var(--primary2));
  color: white;
  box-shadow: var(--shadow);
}

.main{
  display: grid;
  grid-template-columns: 1fr 0.85fr;
  gap: 1.1rem;
  padding: 1.4rem 0 2rem;
}

.board-wrap{
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: var(--r);
  padding: 1rem;
  box-shadow: var(--shadow);
}

.status{
  font-weight: 800;
  padding: 0.75rem 0.8rem;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: rgba(0,0,0,0.12);
  margin-bottom: 0.9rem;
}
:root[data-theme="light"] .status{ background: rgba(255,255,255,0.65); }

.board{
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.7rem;
}

.cell{
  aspect-ratio: 1 / 1;
  border-radius: 18px;
  border: 1px solid var(--border);
  background: rgba(0,0,0,0.12);
  display: grid;
  place-items: center;
  font-size: clamp(2.2rem, 5vw, 3.2rem);
  font-weight: 900;
  cursor: pointer;
  user-select: none;
}
:root[data-theme="light"] .cell{ background: rgba(255,255,255,0.65); }
.cell:focus{
  outline: none;
  box-shadow: 0 0 0 4px rgba(124,92,255,0.18);
  border-color: rgba(124,92,255,0.65);
}
.cell.win{
  border-color: rgba(102,255,179,0.85);
  box-shadow: 0 0 0 4px rgba(102,255,179,0.16);
}

.controls{
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.side{
  display: grid;
  gap: 1rem;
}
.card{
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: var(--r);
  padding: 1rem;
  box-shadow: var(--shadow);
}
.card h2{ margin: 0 0 0.5rem; font-size: 1.1rem; }
.card ul{ margin: 0; padding-left: 1.1rem; color: var(--muted); }
.muted{ color: var(--muted); }
.small{ font-size: 0.9rem; }

.score-grid{
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.7rem;
}
.score{
  border: 1px solid var(--border);
  background: rgba(0,0,0,0.12);
  border-radius: 16px;
  padding: 0.75rem;
}
:root[data-theme="light"] .score{ background: rgba(255,255,255,0.65); }
.score .k{ color: var(--muted); font-weight: 700; font-size: 0.85rem; }
.score .v{ font-size: 1.6rem; font-weight: 900; margin-top: 0.15rem; }

.footer{
  border-top: 1px solid var(--border);
  padding: 1.2rem 0 2rem;
}

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