*{margin:0;padding:0;box-sizing:border-box}
html,body{width:100%;height:100%;overflow:hidden;background:#0a0a1a;font-family:'Segoe UI','PingFang SC','Microsoft YaHei',sans-serif;color:#fff}
.game-container{display:flex;flex-direction:column;align-items:center;justify-content:center;height:100vh;padding:8px}
.game-header{display:flex;align-items:center;justify-content:space-between;width:100%;max-width:720px;padding:4px 12px;margin-bottom:4px}
.game-title{font-size:18px;font-weight:700;letter-spacing:1px}
.back-btn{text-decoration:none;color:#90caf9;font-size:13px;padding:4px 12px;border:1px solid rgba(144,202,249,0.3);border-radius:4px;transition:all .2s}
.back-btn:hover{background:rgba(144,202,249,0.15)}
canvas{display:block;border-radius:8px;box-shadow:0 4px 24px rgba(0,0,0,0.5);cursor:crosshair}
.help-text{font-size:11px;color:#666;margin-top:6px;text-align:center}