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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 600px;
    margin: 2rem auto;
    padding: 0 1rem;
}

header h1 {
    text-align: center;
    margin-bottom: 2rem;
    color: #2c3e50;
}

#todo-form {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

#todo-input {
    flex: 1;
    padding: 0.75rem;
    border: 2px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

#todo-input:focus {
    outline: none;
    border-color: #3498db;
}

button {
    padding: 0.75rem 1.5rem;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s;
}

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

button:active {
    transform: scale(0.98);
}

.filters {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.filters button {
    flex: 1;
    padding: 0.5rem;
    background-color: #ecf0f1;
    color: #7f8c8d;
}

.filters button.active,
.filters button:hover {
    background-color: #3498db;
    color: white;
}

#todo-list {
    list-style: none;
    margin-bottom: 2rem;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    background-color: white;
    border-radius: 4px;
    margin-bottom: 0.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

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

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #95a5a6;
}

.todo-checkbox {
    width: 1.25rem;
    height: 1.25rem;
    margin-right: 1rem;
    cursor: pointer;
}

.todo-text {
    flex: 1;
    font-size: 1.1rem;
}

.todo-actions {
    display: flex;
    gap: 0.5rem;
}

.todo-actions button {
    padding: 0.25rem 0.5rem;
    font-size: 0.875rem;
}

.edit-button {
    background-color: #f39c12;
}

.edit-button:hover {
    background-color: #d35400;
}

.delete-button {
    background-color: #e74c3c;
}

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

.todo-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background-color: white;
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

#todo-count {
    font-weight: bold;
    color: #2c3e50;
}

#clear-completed {
    background-color: #95a5a6;
}

#clear-completed:hover {
    background-color: #7f8c8d;
}

/* Responsive design */
@media (max-width: 480px) {
    .container {
        margin: 1rem auto;
        padding: 0 0.5rem;
    }
    
    #todo-form {
        flex-direction: column;
    }
    
    #todo-input {
        margin-bottom: 0.5rem;
    }
    
    .filters {
        flex-wrap: wrap;
    }
    
    .filters button {
        flex: 1 1 50%;
    }
    
    .todo-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .todo-actions {
        align-self: flex-end;
    }
}