body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f9f9f9;
}

header {
  text-align: center;
  padding: 2rem 1rem;
  background-color: #222;
  color: #fff;
}

.container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
  padding: 2rem 1rem;
}

.card {
  flex: 1 1 250px;
  max-width: 300px;
  padding: 1.5rem;
  border-radius: 10px;
  color: #fff;
  text-align: center;
  transition: transform 0.2s;
}

.card:hover {
  transform: translateY(-5px);
}

.btn {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  border-radius: 5px;
  text-decoration: none;
  background-color: rgba(255, 255, 255, 0.2);
  color: #fff;
  transition: background-color 0.2s;
}

.btn:hover {
  background-color: rgba(255, 255, 255, 0.4);
}

.card:nth-child(1) {
  background-color: #f44336;
}
.card:nth-child(2) {
  background-color: #e91e63;
}
.card:nth-child(3) {
  background-color: #9c27b0;
}
.card:nth-child(4) {
  background-color: #673ab7;
}
.card:nth-child(5) {
  background-color: #3f51b5;
}
.card:nth-child(6) {
  background-color: #2196f3;
}
.card:nth-child(7) {
  background-color: #03a9f4;
}
.card:nth-child(8) {
  background-color: #00bcd4;
}
.card:nth-child(9) {
  background-color: #009688;
}
.card:nth-child(10) {
  background-color: #4caf50;
}
.card:nth-child(11) {
  background-color: #6e9b3b;
}
.card:nth-child(12) {
  background-color: #a6b427;
}