:root{--color-surface:#fff;--color-text:#0b0b0f;--font-sans:system-ui, -apple-system, "Segoe UI", Roboto, sans-serif}*{box-sizing:border-box}html,body{margin:0;padding:0}body{font-family:var(--font-sans);background:var(--color-surface);color:var(--color-text);-webkit-font-smoothing:antialiased}main{max-width:640px;margin:0 auto;padding:3rem 1.5rem}