body{background:url("https://blog-imgs-135.fc2.com/z/i/g/zignition/210311b.png") repeat;animation:bg 30s linear infinite;color:#000;font-family:Verdana}

@keyframes bg{to{background-position:-1000px 0}}

main{width:800px;margin:auto;background:#000;border:3px solid #0f0;padding:20px




`