:root{--board-size:480px;--cell-size:calc(var(--board-size)/8);}*{box-sizing:border-box}body{font-family:system-ui,-apple-system,"Hiragino Kaku Gothic ProN","Noto Sans JP",Segoe UI,Roboto,Arial;margin:20px;background:#f3f4f6;color:#111}h1{margin:0 0 8px 0;font-size:20px}header{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}.container{max-width:760px;margin:0 auto}.board{width:var(--board-size);height:var(--board-size);background:#0b6623;display:grid;grid-template-columns:repeat(8,1fr);grid-template-rows:repeat(8,1fr);gap:4px;padding:4px;border-radius:8px;box-shadow:0 4px 12px rgba(0,0,0,0.15)}.cell{background:rgba(0,0,0,0.08);position:relative;border-radius:6px;display:flex;justify-content:center;align-items:center;cursor:pointer;user-select:none}.cell.disabled{opacity:0.85;cursor:default}.disc{width:80%;height:80%;border-radius:50%;box-shadow:inset 0 -6px 6px rgba(0,0,0,0.25)}.disc.black{background:linear-gradient(#111,#222)}.disc.white{background:linear-gradient(#fff,#ddd);border:1px solid #ddd}.hint{width:24%;height:24%;border-radius:50%;background:rgba(255,255,255,0.85);box-shadow:0 1px 2px rgba(0,0,0,0.2)}.controls{margin-top:12px;display:flex;gap:8px;align-items:center}button{padding:8px 12px;border-radius:6px;border:1px solid #ddd;background:#fff;cursor:pointer}button:active{transform:translateY(1px)}.message{margin-left:12px;color:#444}
@media (max-width:600px){:root{--board-size:360px}}