:root{--pad: 14px}*{box-sizing:border-box}body{margin:0;font:14px/1.4 system-ui,sans-serif}.container{margin:0 auto}.topbar{display:flex;gap:10px;justify-content:space-between;align-items:center;background:#f5f5f5;border-bottom:1px solid #e5e5e5}.topbar .spacer{flex:1}nav a{text-decoration:none;margin:.275rem}button{padding:6px 12px;cursor:pointer}.form{display:grid;gap:10px;max-width:360px}label{display:grid;gap:6px}.error{color:#c62828}.card{border:1px solid #e5e5e5;padding:var(--pad);border-radius:10px}