If you want to change color of products slider arrows you need use some image editor because they are loaded from the directory wp-content/themes/blanco/images/slide_next.png and wp-content/themes/blanco/images/slide_prev.png.
Your site is displayed well on mobile devices. Please clarify what is wrong with responsiveness.
Also the currency is set to $. Could you please clarify with more details?
I have fixed the currency in woocommerce myself. Is there a global CSS panel to change the button colors and hover colors for links? If you look at the social media icons on my website you will notice they do not match the rest of the color scheme. How do I change that?