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

body {
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    max-width: 600px;
    margin: 40px auto;
    padding: 20px;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    margin-bottom: 20px;
    color: #2c3e50;
}

.input-section {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

#todoInput {
    flex: 1;
    padding: 10px;
    font-size: 16px;
    border: 1px solid #ddd;
    border-radius: 4px;
    outline: none;
}

#todoInput:focus {
    border-color: #3498db;
}

#addBtn {
    padding: 10px 20px;
    font-size: 16px;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

#addBtn:hover {
    background-color: #2980b9;
}

#todoList {
    list-style: none;
}

.todo-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px;
    margin-bottom: 8px;
    background-color: #f8f9fa;
    border-radius: 4px;
    transition: background-color 0.3s;
}

.todo-item:hover {
    background-color: #e9ecef;
}

.todo-item.completed {
    background-color: #e9ecef;
    opacity: 0.7;
}

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

.todo-content {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
}

.todo-checkbox {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.todo-text {
    flex: 1;
    font-size: 16px;
}

.todo-input {
    flex: 1;
    padding: 5px;
    font-size: 16px;
    border: 1px solid #ddd;
    border-radius: 4px;
    outline: none;
}

.todo-actions {
    display: flex;
    gap: 5px;
}

.todo-btn {
    padding: 5px 10px;
    font-size: 14px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.edit-btn {
    background-color: #f39c12;
    color: white;
}

.edit-btn:hover {
    background-color: #e67e22;
}

.save-btn {
    background-color: #27ae60;
    color: white;
}

.save-btn:hover {
    background-color: #219a52;
}

.cancel-btn {
    background-color: #95a5a6;
    color: white;
}

.cancel-btn:hover {
    background-color: #7f8c8d;
}

.delete-btn {
    background-color: #e74c3c;
    color: white;
}

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

@media (max-width: 480px) {
    .container {
        margin: 20px;
        padding: 15px;
    }

    .input-section {
        flex-direction: column;
    }

    .todo-item {
        flex-direction: column;
        align-items: flex-start;
    }

    .todo-actions {
        margin-top: 10px;
    }
}