:root{
  --bg:#0b1220; --panel:#0f1b31; --ink:#eaf1ff; --muted:#a8b0c6; --brand:#5aa2ff; --good:#22c55e; --bad:#ef4444;
}
*{box-sizing:border-box}
body{margin:0;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Inter,Arial;background:var(--bg);color:var(--ink);display:flex;align-items:center;justify-content:center;min-height:100vh;padding:16px}
.wrap{max-width:980px;width:100%}

header{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-bottom:14px;flex-wrap:wrap}
h1{font-size:20px;font-weight:800;margin:0}
.toolbar{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
button, select{background:#14213b;color:var(--ink);border:1px solid rgba(255,255,255,.2);border-radius:10px;padding:8px 12px;cursor:pointer}
.primary{background:linear-gradient(180deg,#7bb2ff,#3b82f6);border:0;box-shadow:0 8px 14px rgba(59,130,246,.35)}
.ghost{background:#16223a}

.stats{display:flex;gap:10px;flex-wrap:wrap}
.stat{background:var(--panel);padding:8px 12px;border-radius:10px;font-size:14px;border:1px solid rgba(255,255,255,.12)}

.grid{display:grid;gap:12px;/* kolom diatur via CSS var */ grid-template-columns:repeat(var(--cols,4),1fr)}
.card{position:relative;aspect-ratio:1/1;cursor:pointer;perspective:700px;outline:none;border-radius:12px}
.inner{position:absolute;inset:0;transition:transform .55s;transform-style:preserve-3d;border-radius:12px}
.card.flipped .inner{transform:rotateY(180deg)}
.front,.back{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;border-radius:12px;font-weight:800;backface-visibility:hidden;user-select:none}
.front{background:var(--panel);color:var(--muted);font-size:clamp(18px,6vw,28px)}
.back{background:linear-gradient(180deg,#7bb2ff,#3b82f6);color:white;transform:rotateY(180deg);font-size:clamp(22px,7vw,34px)}

.card.matched .back{background:var(--good)}
.card.wrong .inner{animation:shake .35s}
@keyframes shake{
  0%{transform:rotateY(180deg) translateX(0)}
  25%{transform:rotateY(180deg) translateX(-6px)}
  50%{transform:rotateY(180deg) translateX(6px)}
  100%{transform:rotateY(180deg) translateX(0)}
}
.card.matchPulse .back{animation:pulse .45s ease}
@keyframes pulse{
  0%{transform:rotateY(180deg) scale(1)}
  70%{transform:rotateY(180deg) scale(1.06)}
  100%{transform:rotateY(180deg) scale(1)}
}

.overlay{position:fixed;inset:0;background:rgba(0,0,0,.55);display:none;align-items:center;justify-content:center;color:white;z-index:50}
.overlay.show{display:flex}
.overlay .box{background:#0f1b31;padding:20px;border-radius:16px;text-align:center;max-width:360px;width:100%;border:1px solid rgba(255,255,255,.12)}
.overlay h2{margin:0 0 12px}
.actions{display:flex;gap:8px;justify-content:center;margin-top:12px}
.leader{background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.12);border-radius:12px;padding:10px;margin-top:10px;text-align:left}
.leader .ttl{font-weight:800;margin-bottom:6px}
.leader .rows{display:grid;gap:6px}

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

.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

/* confetti */
.confetti{position:fixed;pointer-events:none;z-index:60;width:8px;height:12px;opacity:.9;will-change:transform,opacity;border-radius:2px}