body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f9;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.app-container {
    background-color: #fff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    width: 300px;
}

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

.input-container {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
}

#todo-input {
    width: 70%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
}

#add-todo-btn {
    padding: 10px 15px;
    background-color: #28a745;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

#add-todo-btn:hover {
    background-color: #218838;
}

ul {
    list-style-type: none;
    padding: 0;
}

li {
    background-color: #f8f9fa;
    padding: 10px;
    margin-bottom: 5px;
    border-radius: 5px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

li.completed {
    text-decoration: line-through;
    color: #6c757d;
}

button {
    background-color: transparent;
    border: none;
    cursor: pointer;
    color: #dc3545;
}

button:hover {
    color: #c82333;
}