body {
 font-family: system-ui, Arial, sans-serif;
 margin: 0;
 background: #eef3ef;
 color: #123722;
}
header{background:#375544;color:#fff;padding:1.5rem;text-align:center}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;padding:1rem}
.card{
 background:white;border-radius:12px;padding:1.2rem;text-align:center;
 border:3px solid #8fbfa5;cursor:pointer;font-size:1.1rem;
}
.card.active{background:#8fbfa5;color:white;border-color:#375544}
button{
 padding:1rem;width:90%;margin:1rem auto;display:block;border-radius:10px;
 border:none;background:#375544;color:white;font-size:1.2rem;
}
.hidden{display:none}
footer{text-align:center;padding:1rem;font-size:.9rem;color:#375544}