body{margin:0;font-family:system-ui,sans-serif;background:#f5f5f5;color:#212121}.header,.footer{background:#222;color:#fff;padding:1rem}.header nav a{color:#fff;margin:0 1rem;text-decoration:none}main{padding:2rem;max-width:700px;margin:0 auto}.profile-img{width:120px;border-radius:50%;margin-bottom:1rem}section{margin-bottom:2rem}