body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

.container {
    width: 80%;
    margin: auto;
    overflow: hidden;
    padding: 20px;
}

h1 {
    text-align: center;
    color: #333;
}

#todo-form {
    display: flex;
    margin-bottom: 20px;
}

#todo-input {
    flex: 1;
    padding: 10px;
    font-size: 16px;
}

button {
    padding: 4px 12px;
    background: #4CAF50;  /* 使用一个更友好的绿色 */
    color: #fff;
    border: none;
    border-radius: 5px;  /* 添加圆角 */
    cursor: pointer;
    font-size: 14px;
    font-weight: bold;
    text-transform: uppercase;  /* 将文字转换为大写 */
    letter-spacing: 1px;  /* 增加字母间距 */
    transition: all 0.3s ease;  /* 添加过渡效果 */
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);  /* 添加阴影效果 */
}

button:hover {
    background: #45a049;  /* 稍微深一点的绿色 */
    transform: translateY(-2px);  /* 向上移动2像素 */
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);  /* 增强阴影效果 */
}

button:active {
    transform: translateY(0);  /* 点击时回到原位 */
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);  /* 减弱阴影效果 */
}


#todo-list {
    list-style-type: none;
    padding: 0;
}

#todo-list li {
    background: #fff;
    padding: 10px;
    margin-bottom: 10px;
    border-radius: 5px;
    display: flex;
    align-items: center;
}

#todo-list li input[type="checkbox"] {
    margin-right: 10px;
}

#todo-list li.completed {
    text-decoration: line-through;
    opacity: 0.7;
}