CSS 1.5 vs 2+

A video I saw showed 1.5 have custom colors settings to easily change site-wide colors. However, in 2+ I don't see that feature. I tried to use the CSS override with a simple h1{color: #000000;} but that didn't seem to do anything. Is there a certain way to use that CSS override? Is there a cache option we should check/uncheck? I was able to change the background image without a problem on the settings page, so it is taking my input.

To be Clear... Opigno 1.5 vs 2+ Color Editor

my last subject might have been confusing. I didn't mean version of CSS, but rather how to edit Opignos CSS Themes for global color? I tried an h1 tag in the CSS Override section and it didn't change anything on the site.