:root{--color-bg: #f6f7fb;--color-text: #1f2937;--color-accent: #2563eb}*{box-sizing:border-box}html,body{margin:0;padding:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--color-text);background:var(--color-bg)}