* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
}
body {
  background-color: #f9fafb;
  color: #333;
}
.board-container {
  max-width: 1200px;
  margin: 20px auto;
  padding: 0 16px;
}
header {
  text-align: center;
  margin-bottom: 20px;
}
.board {
  display: flex;
  gap: 16px;
}
.column {
  flex: 1;
  background-color: #e2e8f0;
  border-radius: 8px;
  padding: 12px;
  min-height: 400px;
  display: flex;
  flex-direction: column;
}
.column h2 {
  text-align: center;
  margin-bottom: 8px;
}
.card-container {
  flex-grow: 1;
  padding: 8px;
  overflow-y: auto;
}
.card {
  background-color: #fff;
  padding: 10px;
  margin-bottom: 8px;
  border-radius: 6px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  cursor: grab;
}
.card:active {
  cursor: grabbing;
}
.add-card-btn {
  background-color: #2563eb;
  color: white;
  border: none;
  padding: 8px;
  border-radius: 6px;
  cursor: pointer;
  margin-top: 8px;
  transition: background 0.3s;
}
.add-card-btn:hover {
  background-color: #1e40af;
}
@media (max-width: 768px) {
  .board {
    flex-direction: column;
  }
}