html, body {
  height: 100%;
}
body {
  font-family: 'Poppins', sans-serif;
  background:#f3f6fa;
  color:#333;
  margin:0;
  padding:0 1rem 2rem;
  display:flex;
  flex-direction:column;
  align-items:center;
}

/* Navigation */
nav {
  display: flex;
  justify-content: center;
  gap: 2rem;
  padding: 1rem;
  background: #f8f9fa;
  border: 1px solid #ddd;
  border-radius: 12px;
  margin: 2rem auto 1.25rem;
  width: 480px;
  max-width: 90%;
}
nav a {
  text-decoration: none;
  font-weight: 500;
  color: #333;
  padding: .25rem .4rem;
  border-radius: 6px;
  transition: color .2s ease, background-color .2s ease, transform .2s ease;
}
nav a:hover {
  color: #3b82f6;
  transform: translateY(-2px);
}

nav a.active {
  background: #e0e7ff;
  color: #1e40af;
}

/* Tile */
.card {
  background:#fff;
  padding:1.5rem;
  border-radius:12px;
  box-shadow:0 4px 12px rgba(0,0,0,0.08);
  width:100%;
  max-width:480px;
  margin:0 auto 2rem;
}

/* Content inside tile */
.card h1, .card h2 {
  margin-top:0;
}
.card p {
  line-height:1.6;
  margin:.5rem 0 1rem;
}
.card ul {
  padding-left:1.1rem;
  margin:.25rem 0 1rem;
}
.card li { margin:.25rem 0; }

/* Adaptive sizing */
@media (max-width:600px) {
  nav { gap:1rem; }
  .card { padding:1.25rem; }
}