* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #f5f5f5;
  padding: 2rem;
  line-height: 1.6;
}

.container {
  max-width: 600px;
  margin: 0 auto;
  background: white;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

h1 {
  margin-bottom: 1.5rem;
  color: #333;
}

#add-task-form {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

#task-input {
  flex: 1;
  padding: 0.75rem;
  border: 2px solid #ddd;
  border-radius: 4px;
  font-size: 1rem;
}

#task-input:focus {
  outline: none;
  border-color: #4CAF50;
}

button {
  padding: 0.75rem 1.5rem;
  background: #4CAF50;
  color: white;
  border: none;
  border-radius: 4px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}

button:hover {
  background: #45a049;
}

button:active {
  background: #3d8b40;
}

#task-list {
  list-style: none;
}

.task-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem;
  border-bottom: 1px solid #eee;
  transition: background 0.2s;
}

.task-item:hover {
  background: #f9f9f9;
}

.task-item input[type="checkbox"] {
  width: 1.25rem;
  height: 1.25rem;
  cursor: pointer;
}

.task-item .task-text {
  flex: 1;
  cursor: pointer;
}

.task-item.completed .task-text {
  text-decoration: line-through;
  color: #999;
}

.task-item .delete-btn {
  padding: 0.5rem 1rem;
  background: #f44336;
  font-size: 0.875rem;
}

.task-item .delete-btn:hover {
  background: #da190b;
}

.empty-state {
  text-align: center;
  padding: 2rem;
  color: #999;
}