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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
    Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
  background: linear-gradient(135deg, #a8d8ea 0%, #c4e5f2 100%);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}

.container {
  background-color: #d4e9f5;
  width: 100%;
  max-width: 700px;
  min-height: 400px;
  border-radius: 8px;
  padding: 40px 50px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* 區塊1: App 標題 */
.app-header {
  text-align: center;
  margin-bottom: 30px;
}

.app-header h1 {
  font-size: 2.5rem;
  color: #2c3e50;
  font-weight: 600;
  letter-spacing: 2px;
}

/* 區塊2: 輸入區 */
.input-section {
  display: flex;
  gap: 15px;
  margin-bottom: 15px;
}

.todo-input {
  flex: 1;
  padding: 12px 20px;
  font-size: 1rem;
  border: none;
  border-radius: 6px;
  background-color: #ffffff;
  color: #2c3e50;
  outline: none;
}

.todo-input::placeholder {
  color: #a9a9a9;
}

.add-btn {
  padding: 12px 30px;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 6px;
  background-color: #6495ed;
  color: white;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

.add-btn:hover {
  background-color: #4169e1;
}

.add-btn:active {
  transform: scale(0.98);
}

/* 分隔線 */
.divider {
  border: none;
  border-top: 2px solid #2c3e50;
  margin: 20px 0 30px 0;
}

/* 區塊3: ToDo 列表 */
.todo-list {
  list-style: none;
}

.todo-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 0;
  margin-bottom: 10px;
}

.todo-text {
  font-size: 1.1rem;
  color: #6b7280;
  display: flex;
  align-items: center;
}

.todo-text::before {
  content: '•';
  margin-right: 15px;
  font-size: 1.5rem;
  color: #6b7280;
}

.delete-btn {
  padding: 8px 25px;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 6px;
  background-color: #f08080;
  color: #2c3e50;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

.delete-btn:hover {
  background-color: #e76f6f;
}

.delete-btn:active {
  transform: scale(0.98);
}

/* 響應式設計 */
@media (max-width: 600px) {
  .container {
    padding: 30px 20px;
  }

  .app-header h1 {
    font-size: 2rem;
  }

  .input-section {
    flex-direction: column;
  }

  .todo-text {
    font-size: 1rem;
  }
}