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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 600px;
    margin: 50px auto;
    background-color: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
}

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

#todoInput {
    flex: 1;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 4px;
    font-size: 16px;
    outline: none;
    transition: border-color 0.3s;
}

#todoInput:focus {
    border-color: #4CAF50;
}

#addButton {
    padding: 12px 24px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s;
}

#addButton:hover {
    background-color: #45a049;
}

.filter-container {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    justify-content: center;
}

.filter-btn {
    padding: 8px 16px;
    background-color: #f0f0f0;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.filter-btn:hover {
    background-color: #e0e0e0;
}

.filter-btn.active {
    background-color: #4CAF50;
    color: white;
}

#todoList {
    list-style: none;
    margin-bottom: 20px;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 15px;
    margin-bottom: 10px;
    background-color: #f9f9f9;
    border-radius: 4px;
    transition: all 0.3s;
}

.todo-item:hover {
    background-color: #f0f0f0;
}

.todo-item.completed {
    opacity: 0.7;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #888;
}

.todo-checkbox {
    width: 20px;
    height: 20px;
    margin-right: 15px;
    cursor: pointer;
}

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

.delete-btn {
    padding: 5px 10px;
    background-color: #f44336;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

.delete-btn:hover {
    background-color: #d32f2f;
}

.stats {
    text-align: center;
    color: #666;
    font-size: 14px;
}