body{margin:0;font-family:Arial;background:#08111f;color:#fff;text-align:center}.bg{position:fixed;inset:0;background:radial-gradient(circle,#1d4ed8,#08111f);animation:pulse 6s infinite alternate;z-index:-1}@keyframes pulse{from{filter:hue-rotate(0)}to{filter:hue-rotate(40deg)}}section{margin:20px auto;max-width:700px;background:#112;padding:15px;border-radius:10px}a,button{margin:8px;padding:10px}