body {
  font-family: 'Arial', sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f5f5f5;
}

header {
  background-color: #3498db;
  color: white;
  padding: 1rem;
  text-align: center;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

.card {
  background-color: white;
  border-radius: 8px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  padding: 20px;
  margin-bottom: 20px;
}

.btn {
  background-color: #3498db;
  color: white;
  border: none;
  padding: 10px 15px;
  border-radius: 4px;
  cursor: pointer;
}

.btn:hover {
  background-color: #2980b9;
}

.pool-item {
  display: inline-block;
  width: 30%;
  margin: 1%;
  vertical-align: top;
}

.history-item {
  margin-bottom: 15px;
  padding: 10px;
  border-bottom: 1px solid #ddd;
}

.copy-btn {
  background-color: #2ecc71;
  color: white;
  border: none;
  padding: 5px 10px;
  border-radius: 4px;
  cursor: pointer;
}

.copy-btn:hover {
  background-color: #27ae60;
}