body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, sans-serif;
  background: #f4f6f9;
}

header {
  padding: 12px;
  background: #2c3e50;
  color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.tabs {
  display: flex;
  position: sticky;
  top: 0;
  background: white;
}

.tabs button {
  flex: 1;
  padding: 12px;
  border: none;
  background: #ecf0f1;
  font-size: 16px;
}

.tabs button.active {
  background: #3498db;
  color: white;
}

#taskContainer {
  padding: 10px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.card {
  background: white;
  padding: 15px;
  border-radius: 12px;
  box-shadow: 0 3px 8px rgba(0,0,0,0.08);
}

.card h3 {
  margin: 0 0 8px 0;
}

.card-buttons {
  margin-top: 10px;
  display: flex;
  justify-content: space-between;
}

.card-buttons button {
  border: none;
  padding: 6px 12px;
  border-radius: 6px;
}

.edit-btn { background: #3498db; color: white; }
.delete-btn { background: #e74c3c; color: white; }

.fab {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: #3498db;
  color: white;
  border: none;
  border-radius: 50%;
  width: 56px;
  height: 56px;
  font-size: 24px;
}

.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  justify-content: center;
  align-items: center;
}

.hidden { display: none; }

.modal-content {
  background: white;
  padding: 20px;
  border-radius: 12px;
  width: 90%;
  max-width: 400px;
}

.modal-buttons {
  margin-top: 15px;
  display: flex;
  justify-content: space-between;
}

.group-header {
  margin: 20px 0 5px 5px;
  font-size: 18px;
  font-weight: bold;
  color: #34495e;
}