To change the Social Link Color in Squarespace, you can find these options.
#1. Open the page containing the Social Link whose color you want to change > Edit Page
#2. Click the Site Styles icon on the top right of the site.
#3. Click COLORS
#4. On the left side, you will see the Theme Color , in my example, it is LIGHTEST 1 . Click the corresponding theme color on the Right side (LIGHTEST 1 )
#5. Scroll to this option, and change the social link color here.
#6. Result