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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #f5f5f5;
    min-height: 100vh;
    padding: 40px 20px;
}

.container {
    max-width: 500px;
    margin: 0 auto;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 30px;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
}

/* 添加待办事项区域 */
.add-todo {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

#todoInput {
    flex: 1;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 16px;
}

#todoInput:focus {
    outline: none;
    border-color: #4a90d9;
}

#addBtn {
    padding: 12px 24px;
    background: #4a90d9;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
}

#addBtn:hover {
    background: #357abd;
}

/* 待办事项列表 */
#todoList {
    list-style: none;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 15px;
    border-bottom: 1px solid #eee;
    gap: 12px;
}

.todo-item:last-child {
    border-bottom: none;
}

/* 复选框样式 */
.todo-item input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

/* 待办事项文本 */
.todo-text {
    flex: 1;
    font-size: 16px;
    color: #333;
}

/* 已完成的待办事项 */
.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #999;
}

/* 删除按钮 */
.delete-btn {
    padding: 6px 12px;
    background: #e74c3c;
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
}

.delete-btn:hover {
    background: #c0392b;
}