:root{--bg:#fff;--text:#0f172a;--card-bg:#f8fafc;--primary:#2563eb}body{background:var(--bg);color:var(--text);margin:0;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif}header{border-bottom:1px solid #e2e8f0;justify-content:space-between;align-items:center;padding:1rem 2rem;display:flex}header h1{margin:0;font-size:1.5rem}header button{cursor:pointer;background:0 0;border:1px solid #cbd5e1;border-radius:.4rem;padding:.4rem .8rem}