:root{color:#1f2937;background:#f8fafc;font-family:Arial,sans-serif}*{box-sizing:border-box}body{margin:0}#root{min-height:100vh}.app{place-items:center;min-height:100vh;padding:24px;display:grid}h1{text-align:center;margin:0;font-size:clamp(2rem,5vw,3.5rem);font-weight:700}