:root {
  --bg: #0d1424;
  --bg2: #131d33;
  --panel: #1a2742;
  --line: #28385c;
  --text: #e8eefc;
  --muted: #93a3c4;
  --accent: #ffcf4d;
  --accent2: #ffe39a;
  --on: #ffcf4d;
  --on-glow: rgba(255, 207, 77, 0.55);
  --off: #1d2a47;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  background: radial-gradient(1200px 600px at 50% -10%, var(--bg2), var(--bg));
  color: var(--text);
  min-height: 100vh;
  -webkit-text-size-adjust: 100%;
}

.wrap {
  max-width: 560px;
  margin: 0 auto;
  padding: 24px 18px 48px;
}

.head { text-align: center; margin-bottom: 18px; }
h1 {
  margin: 0 0 6px;
  font-size: 1.9rem;
  letter-spacing: 0.04em;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.lead { margin: 0; color: var(--muted); font-size: 0.92rem; line-height: 1.6; }

.sec-title { font-size: 1.05rem; margin: 8px 0 12px; text-align: center; color: var(--accent2); }

.levels { display: grid; gap: 12px; }
.level-btn {
  width: 100%;
  text-align: left;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 14px 16px;
  color: var(--text);
  cursor: pointer;
  transition: transform 0.12s, border-color 0.12s, background 0.12s;
}
.level-btn:hover { border-color: var(--accent); transform: translateY(-2px); }
.level-btn .lv-name { font-size: 1.1rem; font-weight: 700; }
.level-btn .lv-meta { display: block; color: var(--muted); font-size: 0.82rem; margin-top: 4px; }
.level-btn .lv-best { display: block; color: var(--accent); font-size: 0.82rem; margin-top: 4px; }

.rules { margin-top: 18px; background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 4px 14px; }
.rules summary { cursor: pointer; padding: 10px 0; color: var(--accent2); font-weight: 600; }
.rules ul { margin: 0 0 12px; padding-left: 18px; color: var(--muted); line-height: 1.7; font-size: 0.9rem; }

.hud {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-bottom: 16px;
}
.stat {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 8px 14px;
  text-align: center;
  min-width: 78px;
}
.stat-label { display: block; color: var(--muted); font-size: 0.72rem; }
.stat-val { display: block; font-size: 1.3rem; font-weight: 700; }

.board {
  display: grid;
  gap: 8px;
  margin: 0 auto 20px;
  max-width: 420px;
}
.cell {
  aspect-ratio: 1 / 1;
  border: none;
  border-radius: 12px;
  background: var(--off);
  box-shadow: inset 0 0 0 1px var(--line);
  cursor: pointer;
  transition: background 0.16s, box-shadow 0.16s, transform 0.08s;
  position: relative;
}
.cell::after {
  content: "";
  position: absolute;
  inset: 26%;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.04);
  transition: background 0.16s, box-shadow 0.16s;
}
.cell.on {
  background: linear-gradient(145deg, var(--on), #f5b800);
  box-shadow: 0 0 18px var(--on-glow), inset 0 0 0 1px rgba(255, 255, 255, 0.25);
}
.cell.on::after { background: rgba(255, 255, 255, 0.85); box-shadow: 0 0 10px rgba(255, 255, 255, 0.7); }
.cell:active { transform: scale(0.94); }

.controls { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.btn {
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  color: #2a2000;
  border: none;
  border-radius: 12px;
  padding: 12px 20px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.12s, filter 0.12s;
}
.btn:hover { transform: translateY(-2px); filter: brightness(1.05); }
.btn.ghost {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--line);
}
.btn.ghost:hover { color: var(--text); border-color: var(--accent); }

.clear-card { text-align: center; background: var(--panel); border: 1px solid var(--line); border-radius: 18px; padding: 28px 18px; }
.clear-emoji { font-size: 3rem; animation: pop 0.5s ease; }
.clear-card h2 { margin: 6px 0 10px; font-size: 1.6rem; }
.clear-summary { color: var(--text); font-size: 1.05rem; margin: 6px 0; }
.clear-best { color: var(--accent); font-weight: 700; min-height: 1.2em; margin: 6px 0 18px; }

.foot { text-align: center; color: var(--muted); font-size: 0.76rem; margin-top: 28px; }

@keyframes pop { 0% { transform: scale(0.4); } 70% { transform: scale(1.15); } 100% { transform: scale(1); } }

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}