Color/ Overlay showcase image one-page-site skeleton

Hello everyone! I am very new with twig and grav, so i decided to dive into it. But my first problem is where i can change the color/ overlay of the showcase image. I searched a lot in css and compiled css and of course in the SCSS files but i can find out where the overlay and blueish color came from. Please help me.

that’s actually being set by the showcase twig in the antimatter theme:


{% set showcase_image =|first.grayscale().contrast(20).brightness(-125).colo rize(-35,81,122) %}

Specifically the colorize() bit.

thanks! i really enjoy learning grav.