:root{--bg: #ffffff;--fg: #111;--primary: #4a90e2}*{box-sizing:border-box}html,body,#root{height:100%}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto;background:var(--bg);color:var(--fg)}.container{padding:16px;max-width:900px;margin:0 auto}h1{font-size:1.25rem;margin:.5rem 0;color:var(--primary)}