:root{--brand-primary:#1a1a1a;--brand-accent:#4f46e5;--brand-surface:#f6f6f7;--brand-font-heading:system-ui,sans-serif;--brand-radius:8px}*{box-sizing:border-box}body,html{margin:0;padding:0}body{background:var(--brand-surface);color:#222;font-family:system-ui,-apple-system,sans-serif;line-height:1.6}h1,h2,h3{font-family:var(--brand-font-heading);color:var(--brand-primary)}a{color:var(--brand-accent)}.btn{display:inline-block;padding:.6rem 1.2rem;border:0;border-radius:var(--brand-radius);background:var(--brand-accent);color:#fff;font:inherit;cursor:pointer}.btn-plain{background:none;color:var(--brand-accent);padding:0;text-decoration:underline}