body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
}

#todo-app {
    width: 400px;
    margin: 50px auto;
}

#new-task-input {
    width: 300px;
    padding: 10px;
    font-size: 16px;
}

#add-task-button {
    padding: 10px;
    font-size: 16px;
}

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

.task-item {
    background-color: #fff;
    margin-top: 10px;
    padding: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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