body{font-family:system-ui,Segoe UI,Roboto,Arial,sans-serif;margin:24px;color:#222}
header,nav,section{max-width:900px;margin:auto}
nav ul{display:flex;gap:1rem;list-style:none;padding:0}
.card{border:1px solid #ccc;border-radius:12px;padding:16px;margin-bottom:16px}
button,input,select,textarea{padding:8px;border:1px solid #aaa;border-radius:8px}
ul{padding-left:18px}