.topics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 30px;              /* space between cards */
  max-width: 1000px;      /* keeps them from stretching too wide */
  margin: 40px auto;      /* centers the whole grid */
  padding: 0 20px;        /* space inside the container */
}

.topic {
  display: block;
  background: #f1f1f1;
  padding: 20px;          /* space inside each card */
  border-radius: 8px;
  text-align: center;
  font-weight: bold;
  color: #004080;
  text-decoration: none;
  transition: background-color 0.3s, color 0.3s;
}

.topic:hover {
  background-color: #0066cc;
  color: white;
}