Change Font on add to cart button

I have added some custom CSS to change the padding and background o the 'Add to cart' button. 

I want to have it as the Adelle font which is the one across the site. How do I change this? 

Thanks in advance @tuanphan @Agha_Waqas

Add to Design > Custom CSS

* {
    font-family: 'adelle-web' !important;
}