You have installed a demo from our theme and you want to change the predominants colors.
Please go first to WP-Admin > CROMA > Look and feel.
In this section you will find different color options.
You can also select a color for title divider, widget divider, and backgrounds.
Go to WP-Admin > CROMA > Typography.
Here, you can edit colors and typographies for every heading (Body, h1, h2, h3, etc.).
In this section you can edit the color for the menu.