Hello,

Please check Appearance > Customize > Additional CSS, remove the code https://gyazo.com/698f72974f10ab9cf46c9cff586dc297

You need to change the title of the product: https://gyazo.com/76e9e41629d6f1a8035ac15255eab112 When you insert the title with capital letters it cannot be changed with CSS.

Please add this code to the Theme Settings > Custom CSS > Global:

body .woocommerce-mini-cart__buttons .btn-cart {
    text-transform: none;
}
body .woocommerce-mini-cart__buttons .checkout {
    text-transform: none;
}

Move all CSS from Additional CSS to Theme Settings > Custom CSS.

Best Regards