/* style.css */ body { margin: 20px; background-color: #000; overflow: hidden; } canvas { display: block; margin: auto; background: radial-gradient(#000, #111); border: 2px solid #5ba3f5; border-radius: 8px; box-shadow: 0 0 20px rgba(190, 190, 190, 0.6); } #startBtn { position: absolute; top: 402px; left: 50%; transform: translate(-50%, -50%); padding: 12px 24px; font-size: 18px; font-weight: bold; color: rgb(163, 97, 204); background: rgba(0, 0, 0, 0.2); border: 2px solid rgb(87, 53, 235); box-shadow: 0 0 16px rgba(109, 139, 236, 0.6); border-radius: 8px; cursor: pointer; z-index: 10; } #soundToggleBtn { position: absolute; top: 36px; left: 44.5%; transform: translate(-50%, -50%); background-color: rgba(0, 0, 0, 0); /* 半透明黒 */ color: rgb(153, 153, 153); font-weight: bold; border: none; font-size: 16px; cursor: pointer; z-index: 10; }