How can I modify theme colours in the Stiletto theme?

[ambleandtwine]

Hello!  I have the Stiletto theme and wanted to change some colours... in the quick cart there are set red and green colours for 'your order qualifies for free shipping' which is light green, and a bit hard to read with my background colour.  There is also a red colour that pops up if you have added something that is not in stock, saying 'all ____ are in your cart' and I want to change that colour as well.  Where can I change these colours in the code or languages?  Thank you for your help.  Elizabeth   

[KetanKumar]

@ambleandtwine 

can you please send store url

[ambleandtwine]

ambleandtwine.com amble-and-twine.myshopify.com

[KetanKumar]

@ambleandtwine 

great thanks but please  share where did you change color if possible to share screenshot 

[ambleandtwine]

I haven’t published Stiletto yet, I’m just working on it. Here are a couple
of screen shots. See the green and red? Just wondering if I can change
those colours to my dark brown brand colour. I was also wondering if there
is a way to change my cart icon from a bag to a cart symbol? Thanks so
much for your help! Elizabeth