How to set 'Local Delivery' as default and customize checkout page colors?

Can someone help me with this? I have 2 delivery methods but somehow the default was set as “Self Collection” and I have customers accidentally checking out with no intentions of doing self collection. How do I move the Local Delivery up and set it as default?

Another question, how do I customise the colours on the check out page? Because when I go to theme setting at “Checkout”, the settings are right but not reflecting on the page.