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

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

.app-container {
    background-color: #fff;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    width: 400px;
    padding: 20px;
}

.app-title {
    text-align: center;
    font-size: 2rem;
    color: #333;
}

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

#todo-input {
    flex-grow: 1;
    padding: 10px;
    font-size: 1rem;
    border: 1px solid #ccc;
    border-radius: 5px;
}

#add-todo-btn {
    padding: 10px 15px;
    font-size: 1rem;
    border: none;
    background-color: #007bff;
    color: white;
    border-radius: 5px;
    margin-left: 10px;
    cursor: pointer;
}

#add-todo-btn:hover {
    background-color: #0056b3;
}

.todo-list {
    margin-top: 20px;
}

.todo-item {
    display: flex;
    justify-content: space-between;
    padding: 10px;
    background-color: #f9f9f9;
    border-radius: 5px;
    margin-bottom: 10px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.todo-item.completed {
    text-decoration: line-through;
    color: #bbb;
}

.todo-item button {
    background: none;
    border: none;
    color: #dc3545;
    cursor: pointer;
}

.todo-item button:hover {
    color: #bb2d3b;
}