Filter for SVG color, use only flex

Other than using root and class combination, is there more way to write a easier maintainable and readable CSS?

useful website: https://stackoverflow.com/questions/22252472/how-to-change-the-color-of-an-svg-element

Good god, i tried fill in CSS, change the fill in SVG files, none works. Until I used filter and it worked like magic, the SVG files just turn into Cyan like i want them to be. Thanks Stackoverflow.