:root{font-family:Arial,Helvetica,sans-serif;color:#111;background:#f4f7fb}*{box-sizing:border-box}body{margin:0;line-height:1.5}nav,header,main,footer{max-width:980px;margin:auto;padding:1rem}nav{background:#082b5c}nav a{color:#fff}header{text-align:center}.panel{background:#fff;border:2px solid #153d6f;border-radius:14px;padding:1rem;margin:1rem 0}.controls{display:grid;gap:.8rem;grid-template-columns:repeat(auto-fit,minmax(210px,1fr))}label{font-weight:700}select,input,button{font:inherit;padding:.7rem}button{cursor:pointer;border:2px solid #082b5c;border-radius:9px;background:#fff;font-weight:700}button:hover,button:focus{outline:4px solid #ffbf00;outline-offset:2px}.board{display:grid;grid-template-columns:repeat(7,minmax(44px,1fr));gap:.4rem;max-width:700px;margin:1rem auto}.cell{aspect-ratio:1/1;min-height:44px;border-radius:50%;background:#e5e7eb;border:3px solid #164c8c}.cell.player{background:#ffd43b}.cell.computer{background:#e03131}.column-controls{display:grid;grid-template-columns:repeat(7,minmax(44px,1fr));gap:.4rem}.column-controls button{padding:.55rem .15rem}.score{display:flex;gap:1rem;flex-wrap:wrap}.score span{background:#eef4fb;padding:.6rem;border-radius:8px}.sr-only{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.help{font-size:.95rem}footer{text-align:center}