*{margin:0;padding:0;box-sizing:border-box}html,body,#app{width:100%;height:100%;min-height:100vh}body{display:flex;align-items:center;justify-content:center;background:#000;font-family:Segoe UI,system-ui,sans-serif}.screen{display:flex;flex-direction:column;align-items:center;justify-content:center;width:100%;height:100%;gap:1.5rem}.mizuki-title{font-size:4rem;font-weight:700;color:#fff;margin:0}.btn-play{padding:1rem 3rem;font-size:1.5rem;font-weight:600;color:#000;background:#fff;border:none;border-radius:8px;cursor:pointer}.btn-play:hover{background:#eee}.auth-text{color:#fff;font-size:1.1rem;margin:0 0 .5rem}.auth-hint{color:#aaa;font-size:.95rem;margin:0 0 1rem}.auth-error{color:#f44;font-size:.9rem;margin:0 0 .5rem}.auth-test{margin-top:1rem}.auth-test a{color:#888;font-size:.85rem}.game-status{color:#fff;font-size:1.2rem;margin:0}.board{display:grid;grid-template-columns:repeat(3,80px);grid-template-rows:repeat(3,80px);gap:6px}.cell{width:80px;height:80px;font-size:2.5rem;font-weight:700;color:#fff;background:#222;border:2px solid #444;border-radius:8px;cursor:pointer}.cell:not(:disabled):hover{background:#333}.cell:disabled{cursor:default}.game-actions{display:flex;gap:1rem}.btn-back,.btn-reset{padding:.6rem 1.5rem;font-size:1rem;color:#fff;background:transparent;border:2px solid #fff;border-radius:8px;cursor:pointer}.btn-back:hover,.btn-reset:hover{background:#ffffff1a}