Change WooCommerce buttons and back to top link colors

Hi there,

I would like to adjust the colors of all buttons from the standard yellow… ?
‘Purchase’/’Sign up Now’ – in woocommerce
‘Proceed to checkout’- in woocommerce
The up arrow at the bottom right of each page when scrolled down.

Also do you think maybe this is something that need building into an update for consistency?

(I have emailed you images however do not appear to be able to post them to the support Forum)

Thank you